
694 F.Supp. 111 (1988)
Felix CAPONE and Patricia Capone, his wife
v.
HARRIS CORPORATION, Harris Graphics Corporation, Harris-Seybold Co., Harris Intertype Corporation and Harris Corporation Commercial Press Division.
Civ. A. No. 88-0405.
United States District Court, E.D. Pennsylvania, Civil Division.
August 17, 1988.
Stuart D. Fiel, Philadelphia, Pa., for plaintiff.
John P. Penders, Philadelphia, Pa., for defendants.

MEMORANDUM AND ORDER
VAN ANTWERPEN, District Judge.
This action was commenced on June 11, 1986 by Writ of Summons filed in the Court of Common Pleas of Philadelphia County under June Term, No. 2416. The Summons, which gave no indication of the nature of the action, was served by certified mail, and return receipts were received by plaintiffs.
On December 5, 1986, a Complaint, setting forth the cause of action, was filed with the Court of Common Pleas and served by ordinary United States mail. On December 26, 1986, Notices of Intention to Take Default pursuant to Pa.R.Civ.P. 237.1 were served by ordinary mail. On January 13, 1987, Judgment by Default was entered against defendants and in favor of plaintiffs.
On February 10, 1987, Petition/Motion of Defendants to Open and/or to Strike Default Judgments was filed in the Court of Common Pleas. Included as Exhibit F was a copy of the complaint. Among defendants' allegations in support of their Petition/Motion was improper service of the complaint. By order of Common Pleas Judge Nelson A. Diaz dated January 12, 1988, the default judgment was opened and vacated. In his opinion, Judge Diaz found that defendants had not received proper notice of filing of suit or entry of default. By Notice of Appeal filed January 21, 1988, plaintiffs appealed Judge Diaz's order to the Superior Court of Pennsylvania. That court has held the appeal in abeyance pending resolution of plaintiffs' Petition for Remand discussed below.
On January 19, 1988, defendants' Petition for Removal was filed with this court. *112 Plaintiffs filed their Petition for Remand on February 16, 1988. Defendants' Answer to plaintiffs' Complaint was filed in this court on February 16, 1988. Plaintiffs based their petition on defendants' failure to file their Petition for Removal within the thirty day period provided by 28 U.S.C. § 1446(b).[1] Defendants, in their answer to plaintiffs' Petition for Remand, argue that they were unable to file a Removal Petition until the question of the default judgment was resolved by Judge Diaz's January 12, 1988 order.
Failure to file a petition for removal within the thirty days provided by § 1446(b) is sufficient ground on which to remand. Blow v. Liberty Travel, Inc., 550 F.Supp. 375 (E.D.Pa.1982). The burden of proof is on the petitioning defendants to establish their right to removal, including their compliance with the requirements of the removal statute. Id. The burden is therefore on the defendants to prove that the petition for removal was timely under § 1446(b).
While there is controversy as to when the defendants were served with the Complaint, there is no doubt that they had received it by February 10, 1987, when it was an exhibit to defendants' petition/motion to open judgment. Defendants have cited no authority for the proposition that pendency of that motion extends the thirty day period. Therefore, February 10, 1987, is the latest date from which the thirty day period can be calculated. The Petition for Removal was filed one year and six days later. The thirty day period is mandatory and cannot be extended by the Court. Sun Oil Co. of Pa. v. Pa. Dept. of Labor & Industry, 365 F.Supp. 1403 (E.D.Pa.1973). Therefore, the plaintiffs' motion to remand will be granted.
An appropriate order follows.

ORDER
AND NOW, this 17th day of August, 1988, upon consideration of PETITION FOR REMAND filed by plaintiffs on February 16, 1988, and DEFENDANTS' ANSWER thereto filed February 18, 1988, it is hereby ORDERED that this matter is REMANDED to the Court of Common Pleas of Philadelphia County, Pennsylvania.
NOTES
[1]  28 U.S.C. § 1446(b) provides:

"(b) The petition for removal of a civil action or proceeding shall be filed within thirty days after the receipt by the defendant, through service or otherwise, of a copy of the initial pleading setting forth the claim for relief upon which such action or proceeding is based, or within thirty days after the service of summons upon the defendant if such initial pleading has then been filed in court and is not required to be served on the defendant, whichever period is shorter.
If the case stated by the initial pleading is not removable, a petition for removal may be filed within thirty days after receipt by the defendant, through service or otherwise, of a copy of an amended pleading, motion, order or other paper from which it may first be ascertained that the case is one which is or has become removable."
