The purpose of this study was to investigate the effects of coping mechanisms on uncertainty and depression. The subjects were 71 cancer patients selected from Junbook National University Hospital, and the data collection period was from June 21 to October 19 of 2000. Uncertainty was measured by using Mishel's Uncertainty Scale, problem- focused coping, and emotional-focused coping. The data was collected by a questionnaire developed by Lee (1984), and then depression measured by using Beck's depression scale. Data was analyzed with SPSS/WIN 7.5 program by Pearson Correlation Coefficients, and Path analysis. The results were as follows : 1. The mean uncertainty score was 59.17, the mean problem-focused coping score was 48.78, the mean emotional-focused coping score was 42.52. 2. The mean depression score was 15.77. 3. Uncertainty in illness was significantly related to depression (p=0.003) and emotional-focused coping (p=0.028), but uncertainty was not associated with coping mechanisms. 4. When analyzed multiple regression between uncertainty, problem-focused coping, emotional- focused coping, and depression, more specifically emotional-focused coping showed a stronger association with depression than problem-focused coping. 5. Depression was highly correlated with economic status (p=0.015), educational background (p=0.005), duration of disease (p=0.045). 6. Problem-focused coping and emotional-focused coping appeared to function as moderators instead mediators on the relation between uncertainty and depression. In addition, as a whole, uncertainty showed a significant moderating effect on depression, while problem-focused coping did on depression. Finally, limitation of present findings were discussed and implications for future studies are suggested.