BACKGROUND: Available literature shows that association of alcohol and/or drug use with unsafe sexual practices is not established, in contradistinction to the well-established association between such substance use and the sexual milieu itself.¦GOAL: To analyze these two kinds of associations in a population-based sample of heterosexuals in France.¦STUDY DESIGN: Cross-sectional telephone survey of the French adult heterosexual population in the early 1990s (n = 4213).¦RESULTS: Subjects at risk were more likely than those not at risk to have consumed alcohol before sex; this was not the case for drug use. However, at-risk subjects who engaged in unsafe practice(s) were not more likely to have consumed alcohol or drugs.¦CONCLUSION: Alcohol consumption appears to be a marker for being in an at-risk situation in France and may be used as such by public health providers. In contrast, the association between alcohol/drug use and unsafe sexual practices is not supported by our study and thus conflicts with prevention strategies to increase compliance with safer sex through alcohol/drug abstinence.