8510 Background: Depression is very common in the elderly and is particularly costly because of associated mortality, excess disability, and interactions with other physical health problems. We aimed to examine the impact of depression on quality of life in the older prostate cancer patients receiving Medicare benefits. METHODS: Data came from the 2003 Cohort VI Baseline Medicare Health Outcomes Survey. Among the 109,115 individuals, only those who were under treatment for prostate cancer and completed the survey themselves were included in this study (n=2,191). Quality of life was assessed using the SF-36 questionnaire and the physical and mental health component scores (higher scores indicating better health) were analyzed. RESULTS: Eighty-eight percent were whites, 75% were married, 76% had at least high school education, 45% were aged 65 to 74, and 55% were aged 75 and older. Those who reported having been depressed in the past two weeks (n=453; 21%) had significantly lower physical health (34.06 vs. 40.24; p < .001) and mental health (41.14 vs. 54.41; p < .001) than those who did not. Similar patterns were observed for those who endorsed questions indicating "depression much of the time in the past year" and "depression most of the time in the past 2 years". CONCLUSIONS: Depression is prevalent among older men diagnosed with prostate cancer, and those who acknowledge being depressed in the past 2 weeks to 2 years have significantly worse mental and physical health. Attention to depression, in addition to prostate cancer specific issues, should be considered among prostate cancer patients who report mental or physical health problems. Early detection and treatment of depression in this population could potentially alleviate their suffering and improve their quality of life. No significant financial relationships to disclose.