Evaluating substance abuse services in ordinary treatment environments requires the use of instruments to measure various dimensions of the intervention process in order to link those processes with client outcomes. This paper reports on the further validation of the Alcohol and other Drug Self-Efficacy Scale (AODSES), designed to measure social workers' perceived self-efficacy with regard to the implementation of substance abuse services. In the first validation study, Kranz (2003) employed exploratory factor analysis to reduce the original 98 items to six factors (43 items) that accounted for 76% of the variance, and demonstrated excellent internal consistency. The current study is a reanalysis of the same data using confirmatory factor analysis, a more stringent test of construct validity. Results were strongly supportive of a 5-factor model with seven of eight indices showing excellent fit of the observed data to the model, and high internal consistency for all subscales. Potential practical applications for clinical evaluation in substance abuse environments and limitations of the study are discussed.