This study assesses whether severity of physical partner aggression is associated with alcohol consumption at the time of the incident, and whether the relationship between drinking and aggression severity is the same for men and women and across different countries. National or large regional general population surveys were conducted in 13 countries as part of the GENACIS collaboration. Respondents described the most physically aggressive act done to them by a partner in the past 2 years, rated the severity of aggression on a scale of 1 to 10, and reported whether either partner had been drinking when the incident occurred. Severity ratings were significantly higher for incidents in which one or both partners had been drinking compared to incidents in which neither partner had been drinking. The relationship did not differ significantly for men and women or by country. We conclude that alcohol consumption may serve to potentiate violence when it occurs, and this pattern holds across a diverse set of cultures. Further research is needed that focuses explicitly on the nature of alcohol's contribution to intimate partner aggression. Prevention needs to address the possibility of enhanced dangers of intimate partner violence when the partners have been drinking and eliminate any systemic factors that permit alcohol to be used as an excuse. Clinical services for perpetrators and victims of partner violence need to address the role of drinking practices, including the dynamics and process of aggressive incidents that occur when one or both partners have been drinking.