ABSTRACT. Objective: Alcohol misuse is substantially infl uenced by social factors, but systematic assessments of social network drinking are typically lengthy. The goal of the present study was to provide further validation of a brief measure of social network alcohol use, the Brief Alcohol Social Density Assessment (BASDA), in a sample of emerging adults. Specifi cally, the study sought to examine the BASDA's convergent, criterion, and incremental validity in relation to well-established measures of drinking motives and problematic drinking. Method: Participants were 354 undergraduates who were assessed using the BASDA, the Alcohol Use Disorders Identifi cation Test (AUDIT), and the Drinking Motives Questionnaire. Results: Signifi cant associations were observed between the BASDA index of alcohol-related social density and alcohol misuse, social motives, and conformity motives, supporting convergent validity. Criterion-related validity was supported by evidence that signifi cantly greater alcohol involvement was present in the social networks of individuals scoring at or above an AUDIT score of 8, a validated criterion for hazardous drinking. Finally, the BASDA index was signifi cantly associated with alcohol misuse above and beyond drinking motives in relation to AUDIT scores, supporting incremental validity. Conclusions: Taken together, these fi ndings provide further support for the BASDA as an effi cient measure of drinking in an individual's social network. Methodological considerations as well as recommendations for future investigations in this area are discussed. (J. Stud. Alcohol Drugs, 74, 810-815, 2013)