OBJECTIVES: To examine patient characteristics, treatment patterns, and healthcare resource utilization of patients with acromegaly in the US.  METHODS: Using a large US claims database, adult individuals with commercial insurance newly diagnosed with acromegaly (ICD-9-CM: 253.0) between 07/01/2007 and 12/31/2010 were identified (the first observed diagnosis was the index date). Patients were required to have 6-month pre-index and 12-month post-index continuous enrollment. Descriptive analysis was performed to describe demographic and clinical characteristics, treatment patterns of acromegaly, and healthcare resource utilization during the post-index period. Similar analysis was conducted for Medicare-eligible patients with supplemental private insurance. RESULTS: This study included 930 commercially-insured patients (mean age: 47.2 years; 52.0% female) and 104 Medicare-eligible patients (mean age: 72.8 years; 36.5% female) with acromegaly. For the commercial population, of the comorbidities evaluated, hypertension (38.2%), diabetes (25.9%), and anthropathy/arthralgia/synovitis (23.7%) had the highest prevalence. More than half of the patients (57.3%) received no treatment; 21.7% received tumor resection surgery and 21.0% received medical therapy as the first-line treatment. During the 12-month post-index period, one-third had inpatient hospitalization and 23.2% had emergency room visit; the mean physician office visit was 17.1. For the Medicare population, hypertension (67.3%), diabetes (36.5%), and anthropathy/arthralgia/synovitis (29.8%) were most prevalent comorbidities. About two-thirds (63.5%) received no treatment; 8.7% received tumor resection surgery and 27.9% received medical therapy as the first-line treatment. More than one-third (34.6%) had inpatient hospitalization and 26.9% had emergency room visit during the 12-month post-index period; the mean physician office visit was 21.1. CONCLUSIONS: Our findings suggest high unmet needs in the population with more than half of patients with acromegaly being untreated. Efforts should be made to understand this untreated population to provide better care. Future research should investigate different treatment options as well as their impact on healthcare costs and healthcare resource utilization.