Recent meta-analysis has demonstrated that attitudes and associates are among the best predictors of antisocial behavior. Despite this finding, there are few psychometrically developed and validated measures of criminal and antisocial attitudes and associates. This study reviews the theoretical and empirical development of the Measures of Criminal Attitudes and Associates (MCAA), which is composed of two parts. Part A is a quantified self-report measure of criminal friends. Part B contains four attitude scales: Violence, Entitlement, Antisocial Intent, and Associates. The MCAA showed reasonable reliability (internal consistency and temporal stability) and appropriate convergent and discriminant validity. Criterion validity was evidenced in the scale's relationship with criminal history variables, and a factor analysis confirmed the four distinct scale domains.