In this study, the authors assessed gender differences between the relationships of self-efficacy and the internal health locus of control with compliance in hemodialysis patients. Using a self-efficacy scale for health-related behavior and the Japanese version of the Health Locus of Control Scale, the authors studied individuals who had been regularly undergoing hemodialysis for longer than 1 year. Blood urea nitrogen, serum potassium, and interdialytic weight gain were used to measure compliance. In men, self-efficacy and the internal health locus of control were negatively correlated with all compliance measures. In women, all the correlations were positive, except for that between self-efficacy and interdialytic weight gain. The authors constructed regression lines for the significant interactions. On the basis of blood urea nitrogen or serum potassium levels, the authors found that female patients who had higher self-efficacy or internal health locus of control were less compliant. The decrease of interdialytic weight gain accompanying increased self-efficacy was more significant in men than it was in women.