A work simulation was conducted to test the effects of workload on stress and performance. Social support was also investigated as a moderator variable. Two hypotheses were tested: (a) stress is an intervening variable between workload and performance and (b) social support moderates the workload-stress relation such that workload leads to lower stress when social support is high. For the 1st hypothesis, a path analysis showed an indirect relation between workload and performance with stress as an intervening variable. For the 2nd hypothesis, there was a significant 3-way interaction between workload, social support, and time. The interaction showed that, in the early Requests for reprints should be sent to Dale N. Glaser, Sharp Health Care, Clinical Outcomes Research,