This cross-sectional study, aimed at evaluating the impact of HIV prevention interventions in Lebanon since 1996, was performed between January 2004 and July 2004 on 3200 Lebanese aged 15-49 years. Of the sexually active respondents, 13.0% of men and 2.6% of women had regular partners other than the spouse but only 25.0% used a condom in their last sexual intercourse. However, 16.8% had sex with casual partners and 71.7% of those used a condom. Knowledge about preventive practices against HIV/AIDS has regressed since 1996, 85.7% compared to 94.9%. Self reports of symptoms suggestive of sexually transmitted disease were 9.1% compared to 5.6% in 1996.