
676 So.2d 86 (1996)
Lisa Smith Munn GUILLOT
v.
Marion Patrick MUNN, Jr.
No. 96-C-0620.
Supreme Court of Louisiana.
June 21, 1996.
PER CURIAM.
Granted in part. The trial court erred in failing to give specific reasons detailing the facts and circumstances warranting a deviation from the child support guidelines. A deviation may be allowed where the application of the guidelines would not be in the best interest of the child or would be inequitable to the parties. La.R.S. 9:315.1(B). Section (C)(2) does allow the trial court to consider, in determining whether to deviate from the guidelines, the legal obligation of a party to support dependents who are not the subject of the action before the court and who are in that party's household. A deviation pursuant to this provision, however, must be supported by an evidentiary basis. In this case, no evidence was introduced as to the expenses incurred in supporting the child born to Mr. Munn's subsequent marriage nor the extent to which his present wife contributes to the support of that child.
Further, the trial court erred in calculating the parties' monthly adjusted gross income. The court reduced Mr. Munn's monthly gross income by $446.00, the guidelines' support obligation for one child based on a monthly income of $2,885.00, as a "credit" for supporting the child born of his subsequent marriage. "Adjusted gross income," as used in the guidelines, means gross income, minus amounts for preexisting child support or spousal support obligations paid to another who is not a party to the proceedings, or on behalf of a child who is not a subject of the action of the court. La.R.S. 9:315. The record reflects that Mr. Munn has no preexisting child support obligation relative to this child.
For the foregoing reasons, the writ is granted in part; the court of appeal judgment is reversed; the trial court judgment is vacated; and the case is remanded to the trial court for a recalculation of the child support obligation consistent with this judgment. Otherwise, the writ application is denied.
REVERSED AND REMANDED.
BLEICH, J., not on panel.
