This study investigated two mediation models of time management. The first model consisted of parts of Macan's (1994) model. The second model combined this model with Karasek's (1998) Job Demand–Control model. Two sets of self-report questionnaires were collected and were analyzed using structural equation modeling. The first model, in which perceived control of time was hypothesized to fully mediate the relation between planning behavior and work strain, job satisfaction, and job performance, was found to be less adequate than the second model, which added workload and job autonomy as independent variables. Results also indicated that partial, rather than full, mediation of perceived control of time fitted the data best. The study demonstrated the importance of studying both planning behavior and job characteristics, which was not part of past research. Copyright © 2004 John Wiley & Sons, Ltd.