Introduction: From all identified HIV positive cases, men's share is far more than women; hence sexual health of men is of special importance in controlling and reducing HIV prevalence. On the other hand, the prominent pattern of virus transmission is changing gradually from transmission due to contaminated injection to transmission through sexual relations in Iran. Recognizing and identifying sexually transmitted pathway among sex workers as well as their clients could contribute in effective intervention, better controlling and reducing HIV prevalence. This study aims to identify some of sex worker client’s characteristics through a cross sectional survey in Tehran capital city of Iran.

Method: Through a "cross sectional" study we asked the informants (sex workers) about characteristics of their clients. Data were collected using both qualitative and quantitative methods. The sample for this study was chosen from sex workers in 22 districts of Tehran. Totally 300 informants were interviewed. The first sampling unites were streets, squares, parks, shopping centers and malls, where these women find their clients.

Findings: This study indicated that, 90 percent of women sex workers have a good understanding and recognize their client’s characteristic. More than half (58.8%) of the informants believe that their clients are adults 30 to 50 years old and 51.6% of them reported that majority of their clients are married. Working hour priority among sex workers also confirms this finding. Among informants 47.7% expressed that their clients are university graduates comparing with 42.8% not finishing high school, and 97.9% of them believe that their clients are employed. Regarding income, 54.7% of the informants reported that their clients are well off and 45.3 % expressed that their clients belong to middle income class. Both qualitative and quantitative data indicate that informants believe their clients live in different districts of Tehran which shows clients vast distribution.

Majority of respondents believe that, clients dissatisfaction with family relations or disturbances in relationship with their wives were the main causes behind their demand for extra marital affair. They also rose following causes for such demand: sexual promiscuity, sexual deviance, sexual desire during times separated from their wives’ (i.e. during wife’s pregnancy, during traveling…) and satisfying sense of authority, power and respect.

Conclusion: In this study women sex workers knowledge regarding their customers’ characteristics was higher in comparison to their peers in other countries. Findings of this study regarding sex workers clients’ age and marital status was compatible with similar studies in other countries. An interesting finding in this study was clients’ income class. Although in previous studies street based sex workers stated that their clients are mainly from middle income class and upper class customers tend to have sexual relation with non-street sex workers. In this study most of the sex workers believe that their clients are employed and belong to upper economic class. This difference could be due to dominance of individual sex working and prohibition and restriction of organized sex working in Iran.