Despite long-standing concern over the sexual health of the population there has been little work undertaken in the UK investigating sexual risk taking and sexual behaviours in the context of substance use. To investigate this further, 270 non-drug treatment seeking members of the public aged between 18 and 66 were administered a questionnaire containing the Alcohol Use Disorders Identification Test (AUDIT), the Drug Abuse Screening Test (DAST), the Severity of Dependence Scale (SDS), the Sexual Risks Scale and Attitudes toward condom use (SRSA), the Sexual Sensation Seeking ScaLe (SSSS); the Hospital Anxiety and Depression ScaLe (HADS), and questions pertaining to sexual episodes proximal to substance use. The population reported a varied history of substances and despite there not being self-awareness of problematic drug use, 39.4% reported above the cut-off mark of six on the DAST. An even greater percentage (57.8%) reported a score above eight on the AUDIT indicating hazardous or harmful drinking behaviour. The substance most often associated with sexual episodes was alcohol, followed by cannabis and ecstasy, and all were most frequently consumed in private houses. Sexual activity after drug use was most frequently circumstantial (i.e. the individual hadn't taken the substance for the specific purposes of sex), and was significantly associated with use of cannabis and ecstasy. The second most frequently reported association between drug use and sex was facilitation of a sexual encounter (i.e. to lower sexual inhibitions, increase self esteem and confidence), which was associated with use of alcohol, cannabis, cocaine and ecstasy. Although it was not possibLe to identify differences in subjective sexual changes after use of particular drugs, subjects reported that compared to sex after alcohol, sex on other drugs was more pleasurable and satisfying, with a greater perception of interpersonal contact with the partner and a greater willingness to sexually experiment. However, this latter change was not associated with changes in the type of sexual activity engaged in. Regression analysis revealed that the greatest subjective changes in sexual experiences were reported by younger participants who had ingested either ecstasy or cannabis prior to the sexual episode. These results are discussed in the context of sexual risk taking and suggest areas of intervention focus which may address substance use and sexuaL risk taking together.