OBJECTIVES: To examine variation in real world health care utilization (HCU) and costs associated with management of brain metastasis (BrMts) by primary malignancy type.  METHODS: A retrospective analysis utilized claims-data from a national health insurer, identifying patients ≥18 yrs with  ≥2 claims ≥7 days apart for BrMets (ICD-9 198.3x) from  January 2004 to April 2010. The index date was the date of the first BrMets claim.  Continuous enrollment (CE) in the health plan for 6 months before (baseline) and 1 month after (follow-up) index date was required; <1 month follow-up was permitted if due to death. Excluding primary brain tumors, baseline CE data (1993 to the index date) was examined to identify the initial primary malignancy. HCU (inpatient stays, office, outpatient and ER visits) and all-cause per-patient per-month (PPPM) costs were examined. RESULTS: A total of 1031 lung and 395 breast cancer patients, and 93 with melanoma were included.  Baseline Charlson comorbidity score was not significantly different.  Mean age at BrRMets diagnosis was highest for lung (60yr) compared to breast cancer (55yr) and melanoma (56yr)[p-value<0.01].  Rates of HCU (events/person-month) were significantly different for melanoma, breast and lung cancer patients: 0.28 versus 0.17 and 0.24 for inpatient stays; 3.16 versus 3.87 and 3.94 for office visits; 2.84 vs. 2.69 and 2.80 for outpatient visits [p-value<0.01].  Total costs PPPM were highest for melanoma ($21,373) compared to breast ($17,933) and lung cancer ($15,199) [p-value=0.001].  Inpatient costs PPPM represented the largest portion of medical costs (44%-50%), but were not significantly different across cohorts: melanoma ($9397), breast ($8781) and lung cancer ($7628).  Pharmacy costs PPPM were highest among melanoma ($1555) then breast ($737) and lung cancer ($720) [p-value <0.001]. CONCLUSIONS: Variation was observed in HCU and costs among BrMets patients based on initial primary tumor type. Analyses of cost studies on BrMets patients need to take this into consideration.