This article presents the proceedings of a symposium at the 2002 RSA Meeting in San Francisco, California. Deborah S. Hasin organized the symposium and co-chaired it with Marc Schuckit. The purpose of the symposium was to provide an overview of what is known about the validity of DSM-IV and ICD-10 alcohol dependence and abuse, with a focus on work done since 1994. Presentations included: (1) Validity of DSM-III-R alcohol dependence in adolescents, by Christopher S. Martin; (2) Reliability and validity of DSM and ICD formulations of alcohol use disorders: findings from epidemiology, by Bridget F. Grant; (3) Validity and reliability of the alcohol-dependence phenotype in the context of genetic studies, by Kathleen K. Bucholz; and (4) DSM-IV and beyond: uniting the clinical utility of categories with the precision of dimensions, by John E. Helzer. The findings supported the validity of DSM-IV alcohol dependence across numerous study designs and samples, suggested some value in a dimensional dependence measure, and raised questions about the validity of the diagnosis of alcohol abuse as currently defined. Marc Schuckit, as discussant for the symposium, placed the issues in perspective for the upcoming DSM-V.