The primary purpose of the present research was to explore the relationship of ability and intrinsic motivation in the prediction of job performance. Intrinsic motivation was traced to two primary determinants. One, an organizational factor, is the extent to which an employee's job is "enriched," or incorporates challenging elements such as autonomy and variety. A second determinant is an individual difference factor--the extent to which the individual desires to achieve and grow. Data were collected from 353 clerical employees in a large, metropolitan bank. Ability was measured by a pre-employment clerical aptitude test; information about job characteristics, individual growth needs, growth satisfaction, and intrinsic motivation was obtained by an employee questionnaire; and job performance was measured by supervisors' evaluations. The hypotheses were tested by hierarchical moderated multiple regression. Ability and intrinsic motivation combined in an additive way but not in an interactive way in predicting job performance. (Author/BW)