aim of this study was to examine factorial invariance of the 20-item Positive and Negative Affect Schedule-Farsi version (PANAS) among male and female university students. A total of 371 undergraduate students (183 males and 188 females) at Shahid Beheshti University completed the Farsi version of the PANAS. First, two-factor model consisted on positive and negative affect were applied to the total sample. Then, single group analysis showed an acceptable two-factor measurement model consisting of positive and negative affect for both male and female groups. Further, based on the one-factor model, results from multi-sample analysis revealed that the Farsi version of the PANAS has the property of sound factorial invariance across sexes, including invariance of measurement residuals, structural covariances and regression measurements. These findings emphasizing the group invariance of factorial structure of PANAS, indicate that PANAS measures a similar construct in these subsamples. The results revealed that the two factors of positive and negative affects in PANAS were perceived in the same manner across students in the two sex groups.