                    FOR PUBLICATION
  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT

KOLELA MPOYO,                                   No. 04-15047
                 Plaintiff-Appellant,
                 v.                               D.C. No.
                                                CV-03-01005-JAT
LITTON   ELECTRO-OPTICAL SYSTEMS,
                                                   OPINION
                Defendant-Appellee.
                                          
         Appeal from the United States District Court
                  for the District of Arizona
         James A. Teilborg, District Judge, Presiding

                   Argued and Submitted
         October 19, 2005—San Francisco, California

                     Filed December 5, 2005

Before: Robert R. Beezer and Alex Kozinski, Circuit Judges,
          and Cormac J. Carney,* District Judge.

                    Opinion by Judge Beezer




  *The Honorable Cormac J. Carney, United States District Judge for the
Central District of California, sitting by designation.

                                15709
15712     MPOYO v. LITTON ELECTRO-OPTICAL SYSTEMS


                         COUNSEL

Kolela Mpoyo, Pro Se, Phoenix, Arizona, for the plaintiff-
appellant.

John Alan Doran, Greenberg Traurig, LLP, Phoenix, Arizona,
for the defendant-appellee.


                         OPINION

BEEZER, Circuit Judge:

   Appellant Kolela Mpoyo appeals the district court’s dis-
missal based on res judicata of his Fair Labor Standards Act
(“FLSA”) and Family and Medical Leave Act (“FMLA”)
claims against his former employer, Appellee Litton Electro-
Optical Systems (“Litton”). We have jurisdiction under 28
U.S.C. § 1291 and we affirm.

                               I

   The relevant facts are not in dispute. Mpoyo filed claims of
racial discrimination and retaliation in violation of Title VII
against his former employer, Litton. The complaint alleged
that his supervisor harassed and defamed him, conspired
against him during his employment, destroyed his reputation
           MPOYO v. LITTON ELECTRO-OPTICAL SYSTEMS         15713
by ordering him to leave the building in a humiliating way,
framed him for removing computer program materials, con-
spired to fire him, conspired to create conflicts between him
and other employees and retaliated against him for reporting
racial epithets. Two years later, after discovery was complete,
expert witness disclosures had passed and summary judgment
motions were fully briefed, Mpoyo sought leave to amend his
complaint to include FMLA and FLSA claims. The district
court denied leave to amend because it would have been
unfairly prejudicial to Litton to add the new claims given that
Mpoyo’s delay was unjustified. The district court granted par-
tial summary judgment in favor of Litton and dismissed
Mpoyo’s remaining two claims for failure to exhaust before
the Equal Employment Opportunity Commission (“EEOC”).
We affirmed the denial of leave to amend, the grant of sum-
mary judgment and the dismissal for failure to exhaust.
Mpoyo v. Litton Electro-Optical Sys., 92 Fed. Appx. 551 (9th
Cir. 2004) (“Mpoyo I”).

   While Mpoyo I was on appeal, Mpoyo filed a new action
in district court (“Mpoyo II”) alleging the FMLA and FLSA
claims of his proposed amended complaint. Mpoyo claimed
Litton placed him on administrative leave instead of leave for
a serious health condition under the FMLA, interfered with
his leave and failed to pay him for overtime work in accor-
dance with the FLSA. The district court dismissed all claims
on res judicata grounds. Mpoyo appeals.

   We review de novo the dismissal based on res judicata.
Stewart v. U.S. Bancorp, 297 F.3d 953, 956 (9th Cir. 2002).

                               II

   [1] We apply a well-established res judicata test to deter-
mine whether Mpoyo’s present claims are barred. Res judi-
cata applies when “the earlier suit . . . (1) involved the same
‘claim’ or cause of action as the later suit, (2) reached a final
judgment on the merits, and (3) involved identical parties or
15714      MPOYO v. LITTON ELECTRO-OPTICAL SYSTEMS
privies.” Sidhu v. Flecto Co., 279 F.3d 896, 900 (9th Cir.
2002).

   [2] Whether the two suits involve the same claim or cause
of action requires us to look at four criteria, which we do not
apply mechanistically: (1) whether the two suits arise out of
the same transactional nucleus of facts; (2) whether rights or
interests established in the prior judgment would be destroyed
or impaired by prosecution of the second action; (3) whether
the two suits involve infringement of the same right; and (4)
whether substantially the same evidence is presented in the
two actions. Chao v. A-One Med. Servs., Inc., 346 F.3d 908,
921 (9th Cir. 2003).

   [3] We use a transaction test to determine whether the two
suits share a common nucleus of operative fact. Int’l Union v.
Karr, 994 F.2d 1426, 1429-30 (9th Cir. 1993). “Whether two
events are part of the same transaction or series depends on
whether they are related to the same set of facts and whether
they could conveniently be tried together.” Western Sys., Inc.
v. Ulloa, 958 F.2d 864, 871 (9th Cir. 1992) (citing Restate-
ment (Second) Judgments § 24(2) (1982)). Because both sets
of Mpoyo’s claims arise from Litton’s conduct while Mpoyo
was an employee and specifically from the events leading to
his termination, his claims relate to the same set of facts. Fur-
thermore, the Title VII, FLSA and FMLA claims form a con-
venient trial unit that discloses a cohesive narrative of an
employee-employer relationship and a controversial termina-
tion. This subsequent action “arises from the same transac-
tion, or series of transactions as the original action” and
therefore satisfies the first criterion. See Western Sys., 958
F.2d at 871 (internal quotation marks omitted).

   [4] The other criteria do not as clearly counsel whether
Mpoyo I and Mpoyo II arise out of the same claim or transac-
tion. The allegations in Mpoyo II involve the same overall
harms and primary rights as the claims decided in Mpoyo I:
in both cases, Mpoyo alleges wrongful discharge. See Monte-
           MPOYO v. LITTON ELECTRO-OPTICAL SYSTEMS         15715
rey Plaza Hotel Ltd. v. Local 483 of the Hotel Employees and
Rest. Employees Union, 215 F.3d 923, 927 (9th Cir. 2000). In
Mpoyo I, however, Mpoyo alleged racial discrimination
(resulting in varied forms of harassment) and retaliation for
reporting “racial epithets” to management in violation of Title
VII. In this action, Mpoyo asserts Littion violated (1) the
FMLA by placing him on administrative leave when he had
a serious medical condition covered under the Act’s leave
provisions and (2) the FLSA by failing to pay him overtime
compensation. The three different Acts arguably address dif-
ferent particular rights and therefore criteria two and three are
not conclusive.

   [5] The fourth criterion asks whether the two actions
require substantially the same evidence. Some evidence of
Litton’s actions would certainly overlap because Mpoyo dis-
putes a single act of termination stemming from a course of
employment. Other evidence supporting the two actions
would likely be distinct: to prove Title VII violations, Mpoyo
would need to demonstrate disparate treatment, protected con-
duct and retaliation; to prove FMLA and FLSA violations,
Mpoyo would need to show protected leave, action in contra-
vention of that leave and overtime work that was not compen-
sated.

   [6] While examination of the latter three criteria does not
yield a clear outcome, Mpoyo I and Mpoyo II clearly share a
common nucleus of operative fact under the first criterion.
The first criterion controls and assures the two suits involve
the same claim or cause of action. It is also appropriate to
weight more heavily the common nucleus of operative fact
criterion here where denial of leave to amend was based on
unjustified untimeliness on the part of the plaintiff that would
cause unfair prejudice to the defendant. We have often held
the common nucleus criterion to be outcome determinative
under the first res judicata element. E.g., Int’l Union, 994 F.2d
at 1429-30 (holding criterion to be outcome determinative and
15716      MPOYO v. LITTON ELECTRO-OPTICAL SYSTEMS
listing cases using the same nucleus of operative fact as the
exclusive factor to bar a second claim under res judicata).

   [7] The second res judicata element is satisfied by a sum-
mary judgment dismissal which is considered a decision on
the merits for res judicata purposes. Hells Canyon Pres.
Council v. U.S. Forest Serv., 403 F.3d 683, 686 (9th Cir.
2005).

   [8] Mpoyo argues the decision was not on the merits
because two of several claims were dismissed without preju-
dice for failure to exhaust before the EEOC. Mpoyo did not
raise this argument before the district court in Mpoyo II. See
Singleton v. Wulff, 428 U.S. 106, 120 (1976) (“It is the gen-
eral rule . . . that a federal appellate court does not consider
an issue not passed upon below.”). Even if he had, Mpoyo’s
argument would fail here because the remainder of the claims,
which arise out of the same transaction, were decided on the
merits when they were dismissed on summary judgment.

   [9] The third element of the res judicata test requires identi-
cal parties or privies in the two actions. The plaintiff and
defendant are identical in both actions. Mpoyo’s argument
that the defendants in the two actions are not completely the
same because Litton was its own entity in the first action,
while, in this action, Litton is a complete integral part of Nor-
throp Grumman fails because (1) Mpoyo specifically named
Litton and not Northrop Grumman in this action, see United
States ex rel. Robinson Rancheria Citizens Council v. Borneo,
Inc., 971 F.2d 244, 249 (9th Cir. 1992), (2) Mpoyo did not
raise the argument below (the complaint only notes that Litton
is now a wholly owned subsidiary of Northrop Grumman),
see Singleton, 428 U.S. at 120, and (3) Mpoyo does not offer
any evidence that the acquisition destroys either identity or
privity.

  [10] Though Mpoyo asserts he was unaware of the FMLA
and FLSA claims when he filed the initial complaint in
          MPOYO v. LITTON ELECTRO-OPTICAL SYSTEMS         15717
Mpoyo I, we have held that “[i]gnorance of a party does not
. . . avoid the bar of res judicata unless the ignorance was
caused by the misrepresentation or concealment of the oppos-
ing party.” Western Sys., 958 F.2d at 871-72 (citing Restate-
ment (Second) Judgments § 26, cmt. j). “Different theories
supporting the same claim for relief must be brought in the
initial action.” Western Sys., 958 F.2d at 871 (citing Restate-
ment (Second) Judgments § 25, cmt. d). There was no bar to
Mpoyo presenting these claims in the original suit, discovery
was completed in Mpoyo I before summary judgment was
granted and the district court in Mpoyo I denied leave to
amend because such action was untimely two years after the
initial complaint was filed. Res judicata “relieve[s] parties of
the costs and vexation of multiple lawsuits, conserve[s] judi-
cial resources, and, by preventing inconsistent decisions,
encourage[s] reliance on adjudication.” Dodd v. Hood River
County, 59 F.3d 852, 863 (9th Cir. 1995) (quoting Allen v.
McCurry, 449 U.S. 90, 94 (1980)). Permitting these later-filed
claims to proceed would create incentive for plaintiffs to hold
back claims and have a second adjudication. Denial of leave
to amend in a prior action based on dilatoriness does not pre-
vent application of res judicata in a subsequent action.

   Our holding in this case is consistent with case law in the
First, Second, Third, Fifth and Eighth Circuits that bars under
res judicata the subsequent filing of claims denied leave to
amend. Northern Assurance Co. of America v. Square D Co.,
201 F.3d 84 (2d Cir. 2000); Huck v. Dawson, 106 F.3d 45 (3d
Cir. 1997); Landscape Props., Inc. v. Whisenhunt, 127 F.3d
678 (8th Cir. 1997); Johnson v. SCA Disposal Servs. of New
England, Inc., 931 F.2d 970 (1st Cir. 1991); Nilsen v. City of
Moss Point, 701 F.2d 556 (5th Cir. 1983) (en banc).

  AFFIRMED.
