OBJECTIVES: The clinical burden of melanoma patients worsens significantly upon metastasis.  However, little is known regarding how hospitalization burden changes upon metastasis.  This study compares the hospitalization burden between metastatic and non-metastatic melanoma patients in a geographically diverse commercially insured US population. METHODS: Insurance claims (January 1, 2004 - June 30, 2009) from the HealthCore Integrated Research Database was used to identify patients aged ≥18 years with ≥2 melanoma claims (ICD-9-CM 172.xx, V10.82).  Two mutually exclusive cohorts were formed: a) metastatic melanoma (MM) cohort with ≥1 claim for metastasis (ICD-9-CM 196.x-198.x), and b) non-MM cohort comprising the remaining patients. The first claims for MM and melanoma were the index-claims for the respective cohorts. Hospitalization burden was compared between the 2 cohorts based on 4 outcomes. The rate of inpatient visits (per-patient-per-month (PPPM)), and the risk of first hospitalization from index-claim, were compared using Poisson and Cox-proportional hazards regression respectively. The mean days to first hospitalization and the mean length of stay (per-patient-per-month (PPPV)) were compared using generalized linear models. RESULTS: The study included 17,756 (mean age 54.4 years, 49.69% female) non-MM patients and 636 (mean age 56.3 years, 41.04% female) MM patients. The proportion of patients with ≥1 hospitalization was 2.4 times higher in the MM compared to the non-MM cohort (45% vs. 19%, p<0.01). Compared to the non-MM cohort, the MM cohort had: 4 times higher PPPM inpatient visit rate (0.04 vs. 0.01, p<0.001), 3-fold greater risk of first hospitalization (HR: 3.01; 95% CI: 2.61-3.46), and shorter mean days to first hospitalization (35 days vs. 309 days, p<0.001). The mean days of inpatient visit (PPPV) were comparable (3.93 vs. 3.54, p=0.32). CONCLUSIONS: The hospitalization burden in metastatic melanoma patients is significantly higher than patients whose melanoma has not progressed to metastasis.  Treatments that improve progression free survival may reduce this burden.