Existing job design models have been criticized for being able to explain affective outcomes more consistently than they do those of task motivation and performance. This study presents an empirical test of several propositions relating to the role of task-related efficacy beliefs as mediators of the relation between job design and task motivation and performance. We begin by highlighting gaps in job design theory, particularly in respect to performance within contemporary work contexts with their increased emphasis on self-management, and draw on social cognitive theory to de scribe the role of self-management efficacy beliefs as a mediator between job design and task motivation. We hypothesize that self-management efficacy will be a first-level outcome of jobs offering opportunities for self-management and also that these beliefs will mediate the relation between opportunities for self-management and task motivation. We tested these hypotheses in a cross-sectional field study (N=270). The results support the need to differentiate between paths from job design that lead to affect and paths that lead to task motivation. There was a strong direct relation between skill utilization and affect (job satisfaction) and task motivation. In contrast, self-management efficacy mediated the path between work method control and task motivation, and the relation between work method control and affect was not significant. Finally, we discuss implications of these results for future research and practice.