Context: Alcohol use is frequently identified as a contributor to risky sexual behaviors; however, research results are mixed. Given the conflicting evidence, researchers have focused on other factors, such as expectations about alcohol's effects that might help explain the relationship of alcohol use and risky sexual behaviors. Methods: Cross-sectional data from 312 sexually experienced males aged 18-30 in a shantytown in Lima, Peru, were used in logistic regression models to identify associations of heavy episodic drinking and sex-related expectations about alcohol with sexual risk behaviors. Results: Heavy episodic drinking was associated with having had two or more sexual partners and having had sex with a casual partner in the past year (odds ratios, 2.8 and 2.5, respectively). After controlling for alcohol consumption, sex-related expectations about alcohol were associated wiih these high-risk sexual behaviors, as well as with not using a condom at last sex (1.2) and not using a condom at last sex with a casual partner(1.3). Conclusion: Beliefs about the effect of alcohol on sexual performance could help explain links between alcohol consumption and risky sexual behavior not completely accounted for by the pharmacological effects of alcohol.