OBJECTIVES: The use of radiopharmaceuticals in oncology is expected to increase over the next few years. There are few studies, however, describing the cost associated with their use. This analysis compared the utilization and cost of patients treated in an outpatient or inpatient setting for prostate cancer (PCa) with bone metastasis (wBM) to those without bone metastasis (w/oBM). METHODS: Patients in the Premier Hospital Database between January 2006 and December 2010 treated in an inpatient or outpatient setting for PCa (ICD9 Codes 185 and 233.4) were included. Patients were required to be ≥40 years of age with no additional cancers. Patients were put into cohorts based on the presence of bone metastasis (ICD9 code 198.5 or the use of zoledronic acid or pamidronate disodium). Utilization of radiopharmaceuticals and PCa-specific treatments were compared, controlling for age, race, hospital, provider payer types, bed size, and admission source and type. Differences in treatments were assessed utilizing logistic regression, while differences in costs were analyzed using gamma distributed generalized linear models with a log link function. RESULTS: There were 23,747 hospitalizations for men wBM and 187,708 hospitalizations for men w/oBM. The mean age of men wBM was 73 years compared to 69 years for men w/oBM.  The use of nuclear medicine-related PCa treatments was higher in patients w/oBM (4.8%) compared to wBM (1.2%). With overall costs of $9,728 in men with wBM and $7,405 (p=0.0006) in those w/oBM, nuclear medicine contributed only 1.2% and 5.2%, respectively (p<0.0001). Room and board contributed the greatest proportion of costs in men wBM (38.9%), while surgery (24.2%), room and board, and radiation (~20% each) were the major contributors in men w/oBM.      CONCLUSIONS: Although increasing in use, currently radiopharmaceuticals do not significantly contribute to the total cost of treating PCa patients in an inpatient or outpatient setting.