Bruxism is a destructive habit that is defined as the nonproductive diurnal or nocturnal clenching or grinding of the teeth. This study investigated whether the combination of physical abnormalities, type A behavior pattern, and the perceived desirability and controllability of life stress are related to bruxism. The subjects for the study were 125 dental patients who were classified as bruxers or nonbruxers by a licensed dentist and who completed two measures, the Jenkins Activity Survey, and a modified version of the Holmes and Rahe Life Events Scale. Regression analyses indicate there is a difference in the separate impact of each variable. Type A behavior and physical abnormalities are significant in a stepwise analysis, while stress is not. Stress appears to be significant only in conjunction with type A behavior, and suggests that the combination of type A behavior, and stress is more predictive of bruxism than either of the individual variables. The linear combination of physical abnormalities, type A behavior, and stress is significant, and suggests that it is the best predictor of bruxism.