We assessed unsafe sexual behaviors of the Nepalese HIV-positive men and their knowledge about the consequences of unsafe sex. We interviewed 167 participants recruited conveniently in the Kathmandu Valley, Nepal. Of total, 125 participants (75%) had sex in the past 6 months, 47% of whom with multiple partners. Fifty-seven (46%) of 123 participants who had sex did not always use condoms; unsafe sex was common in seroconcordant or serodiscordant relationships or in sero-unknown relationships. Only 41% (50/123) participants knew about the possibility of HIV superinfection. Our results suggest the urgent need of HIV prevention interventions for the Nepalese HIV-positive men.