Aim: To evaluate differences between young cocaine users and heroin users (HUs) regarding the prevalence of sexual and injection risk behavior, and HIV, HCV and HBV infection. Methods: Two community cohorts were recruited in Madrid, Barcelona and Seville; 720 cocaine users, of whom 586 had never used heroin (CUs), and 991 HUs were interviewed. Dried blood spot samples were tested. Results: CUs were less marginalized socially than HUs. Only 0.9% had ever injected versus 64.3%; none had ever injected with borrowed syringes versus 25%; 2.2% had an injecting steady partner in the last 12 months versus 24.9%; 4.8% had ever traded sex versus 16.0%. However, 31.0 versus 12.7% had unprotected sex with more than two occasional partners in the last 12 months; 45.0 versus 21.9% had sniffed through tubes used by more than 10 persons. Only 32.3% knew their HIV status versus 80.3%; 0.4 versus 18.1% were HIV positive; 0.9 versus 51.9% were HCV positive, and 1.5 versus 17.0% were HBV positive. Conclusions: The intense cocaine epidemic has hitherto had little impact on either HIV, HBV or HCV in Spain. However, surveillance should be intensified given the high percentage of CUs having unprotected sex with occasional partners.