Men who have sex with men (MSM) and use drugs are at high risk for H V. This study assessed drug and sex-related risk behaviours and sexual identities for MSMIdrug injectors and crack smokers. One hundred and forty four MSM drug injectors and crack smokers from five USA cities were interviewed. One-third of the men were current injectors, twice as many reported lifetime injection. Most (56%) reported sex with women in the prior year; sex trading was reported by 32% with males and 53% with females. There were significant differences between private and public sexual identities. For example, while 31% reported being behaviourally bisexual, only 17% identified themselves to others as bisexual. Drug using MSM are clearly a heterogeneous group and prevention messages addressing this diversity are needed.