Despite precautions taken to guarantee blood safety, in the National Blood Transfusion Center (CNTS) of Abidjan, about 30 regular blood donors are detected with HIV seroconversion each year, two-thirds of them men. A survey through face-to-face interviews was carried out at the CNTS of Abidjan from September 2001 to March 2002 among HIV-positive and HIV-negative regular blood donors, informed about their serologic status. HIV-negative regular blood donors informed about their serologic status since a median time of 67 months (n = 50) disclosed more risky behaviors such as multiple sexual partners (68%) than HIV-positive blood donors informed about their status (n = 112) since a median time of 35 months (41%) (P < 0.001). Condoms were systematically used by 17% of HIV-negative blood donors and 55% of HIV-positive blood donors (P < 0.001). Enhanced counseling and awareness could reduce in the future the number of cases of seroconversion among regular blood donors and improve their subsequent behavior. Blood donors who have unprotected sex with partners of unknown HIV serologic status and especially with casual partners are strongly exposed to HIV transmission and should be discouraged to continue giving blood, after adequate counseling.