Conceptualization and measurement of clinical competence of residents are of interest to medical educators. Yet there is a scarcity of operational tools with satisfactory psychometric support for measuring clinical competence. In this study, we investigated the underlying structure, criterion-related validity and alpha reliability of a brief rating form (20 items) developed to assess clinical competence of residents. The study sample consisted of 882 physicians (654 men, 228 women) in postgraduate training at Thomas Jefferson University Hospital between 1998 and 2000. Construct validity of the form was supported by factor analysis. Two relevant factors emerged: 'Knowledge, Data-Gathering and Processing Skills', and 'Interpersonal Skills and Attitudes'. Criterion-related validity was supported by significant linear associations between factor scores and performance on the medical licensing examinations. Alpha reliability coefficients for the two factors were 0.98 and 0.97, respectively. This brief rating form can be employed as one measure to evaluate clinical competence of residents with reasonable confidence in its measurement properties.