The reliability and validity of a multidimensional 13-item index of competence, called the TMIG Index of Competence, were tested with data of 6776 elderly community residents. The index was designed to measure the higher-level competence which could not be adequately assessed by existing scales. A well-fitted second-order factor model was established. Three first-order factors in the model were named Instrumental Self-Maintenance, Intellectual Activity, and Social Role, and the second-order factor was Competence. The results confirmed high reliability of the index with reliability coefficients of Alpha, test-retest, and correlation between the second-order factor score and the total score, and high validity in terms of construct, discriminant, and predictive validity.