The purpose of this study was to examine the phenotypic, genetic, and environmental relationships between multiple dimensions of Type A behavior and personality. Adult twins (N = 247 pairs) completed a self- report personality measure and a work style questionnaire that measured six facets of Type A behavior: impatience, anger, work involvement, time urgency, job dissatisfaction, and competitiveness. Univariate results suggest that only the job dissatisfaction facet of Type A behavior was explained by non-genetic (environmental) factors. Multivariate results suggest that all of the genetically determined facets of Type A behavior show some correspondence with at least one of the personality factors found in the study, suggesting that some of the phenotypic (observed) relationships could be due to common genetic factors.