This article discusses the results of a corpus-based, quantitative study which was conducted to examine gender differences in conversational interaction in Persian language. The corpus is 20:09 hours of mixed-sex conversational interactions. Amount of speech as a discourse variable was analyzed. The research reveals that statistically significant gender differences are found in the overall distribution patterns. Males do a greater share of talking than females. Gender differences between males and females on the sociolinguistic level are further examined in terms of two factors: topic and the ratio of male to female participants. The results show considerable gender differences in relation to these two factors. Males and females, based on certain topics, show different conversational interactions and the number of male participants has an effect on the language behaviour of men and women.