Objective: Empirical studies indicate that having multiple sex partners is an important risk factor for HIV infection. The present study investigates the extent and determinants of multiple sex partners and condom use among men in Thailand.

Materials and Methods: Data used were from the National Sexual Behavior Study 2006, a national representative sample from Thailand of 3,024 men age 18 to 59. Multivariate analysis is used to examine the determinants of having multiple sex partners and condom use.

Results: About 13% of men reported having multiple sex partners in a 12-month period. Younger men, single men, men with high education, men who drank alcohol more frequently, and men who lived in Bangkok were more likely to have multiple sex partners. Married and single men who have multiple sex partners were about equally likely to use condom when having sex with casual partner (about 85% “always” did). Compared their behavior when they had sex with casual partner, both married and single men who had multiple sex partners were less likely to use condom when they had sex with girlfriend. However, compared to single men, married men were more likely to use a condom when they had sex with girlfriends. Married men typically did not use condom when having sex with their wives.

Conclusion: Due to the inconsistency of using condom with casual sex partners, the risk of transmission of HIV from casual partners to girlfriends or wives remains the serious concern in Thailand. Policy implications on HIV prevention are addressed.

Keywords: Sexual behaviour, Sexual health, Condoms, HIV, Thailand