This dose-escalation study was performed to evaluate safety and efficacy of imiquimod 5% cream in the treatment of uncircumcised men with penile warts associated with the foreskin. The cream was applied 3 times/week (n=34) or once per day (n=30) over 8+/-2 h. Imiquimod 5% cream was safe in both treatment groups. However, the 3 times/week regimen was better tolerated with a lower incidence of local skin reactions. In both groups, the 2 most frequently reported local skin reactions were erythema and erosion; they were more severe with the once-daily dosing. The most frequently reported application site reactions were burning, pruritus and irritation or pain (once-daily patients only). Total clearance was achieved in 62% of the patients in the 3 times/week group and by 57% in the once-daily group. Thus, imiquimod 5% cream administered 3 times/week was the optimal dosing regimen in the treatment of penile warts in uncircumcised men.