The current retrospective observational study was conducted to examine the association between types of chronic conditions and cancer stage at diagnosis among elderly Medicare beneficiaries with prostate cancer using the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database. The study cohort consisted of elderly men (≥66 years) with prostate cancer diagnosed between 2002 and 2009 (N = 103,820). Cancer stage at diagnosis (localized versus advanced) was derived using the American Joint Committee on Cancer classification. Chronic conditions were identified during the year before cancer diagnosis and classified as: (1) only cardiometabolic (CM); (2) only mental health (MH); (3) only respiratory (RESP); (4) CM + MH; (5) CM + RESP; (6) MH + RESP; (7) CM+ MH + RESP; and (8) none of the 3 types of conditions. Chi-square tests and multivariable logistic regressions were used to test the unadjusted and adjusted associations between types of chronic conditions and cancer stage at diagnosis. The highest percentage (5.8%) of advanced prostate cancer was observed among elderly men with none of the 3 types of chronic conditions (CM, RESP, MH). In the adjusted logistic regression, those with none of the 3 types of chronic conditions were 44% more likely to be diagnosed with advanced prostate cancer compared to men with all the 3 types of chronic conditions. Elderly men without any of the selected chronic conditions were more likely to be diagnosed with advanced prostate cancer; therefore, strategies to reduce the risk of advanced prostate cancer should be targeted toward elderly men without these conditions.