OBJECTIVES: To examine the economic burden and health care utilizations of U.S. Medicare patients diagnosed with prostate cancer (PC).  METHODS: A retrospective analysis was conducted using national Medicare claims data (01JAN2008-31DEC2010). Medicare beneficiaries diagnosed with PC were identified using International Classification of Disease, 9^th Revision, Clinical Modification (ICD-9-CM) diagnosis code 185.xx, and the initial diagnosis date designated as the index date. Eligible patients were required to have 1 year continuous enrollment pre- and post-index date. Charlson Comorbidity Index (CCI) score and baseline comorbid conditions were examined for the baseline period. Prescribed medications were captured within 60 days post-index date. Health care utilization and costs were measured for the follow-up period, and costs were adjusted to 2010 U.S. dollars.  RESULTS: A total of 21,616 PC patients were identified, of which 99.2% were male and 84.4% Caucasian. PC patients enrolled in Medicare had a mean age at 76.1 years and more often resided in the Southern U.S. region (37.7%). The baseline CCI score was 1.76, and common comorbid conditions included diabetes (27.3%), tumor (23.6%) and moderate or severe renal disease (21.2%). Simvastatin (7.3%), lisinopril (5.9%) and hydrocodone bitartrate/acetaminophen (5.1%) were the most frequently prescribed medications. During the follow-up period, PC patients had evidence of the following health care utilizations: Medicare carrier (98.0%), Durable Medical Equipment (DME, 32.1%), Home Health Agency (HHA, 12.1%), outpatient visits (75.9%) and inpatient hospital (29.5%), Skilled Nursing Facility (SNF, 7.2%) and hospice admissions (5.4%) and prescription drug (part D event) claims (43.7%). PC patients incurred higher Medicare carrier ($6,330), DME ($328), HHA ($647), outpatient ($19,041), inpatient ($5,814), SNF ($1,229), hospice ($475), pharmacy ($1,144) and total costs ($35,008).  CONCLUSIONS: Patients who were enrolled in Medicare and diagnosed with PC had high utilization of Carrier and outpatient services, as well as frequent comorbid conditions, resulting in considerable health care expenditures.