Prostate cancer lowers the life quality and anxiety and stress intensify this negative effect. The present study was conducted to specify the relationship between life quality and depression, anxiety, and stress in people suffering from prostate cancer. This study is of a descriptive-analytical type in which 100 patients with prostate cancer were selected using convenience sampling and answered the life quality questionnaire and the scale of hospital depression anxiety. Data analysis was done by SPSS 21 software. The average scores of life quality, stress, anxiety, and depression were 50.70, 12.87, 14.60, and 12.52, respectively. A statistically significant inverse relationship was observed between life quality variables with stress (-0.583), depression (-0.329), and anxiety (-0.312). Based on the results of this study, it can be stated that depression and anxiety decrease the life quality. The life of prostate cancer patients seems to be necessary in addition to medical treatments, to implement proper psychological interventions to increase the life quality of prostate cancer patients.