OBJECTIVES Describe health care utilization and costs associated with acromegaly, a rare pituitary disorder that may result in considerable comorbidities and for which data on US health care costs are limited. METHODS  Retrospective claims study in a US commercial health plan analyzed adults with an acromegaly-related diagnosis, procedure, or medication between July 2002 to June 2010. Subjects were observed for six months before their first acromegaly-related claim and until death or disenrollment. RESULTS  A totlal of 1056 subjects had mean (SD) age of 42 (17.2) years on their first acromegaly claim; 49% were male. Common comorbidities included hypertension (23.2%), diabetes (14.4%), and arthropathy (14.3%). Most common specialty office visits included neurology (66.4%), endocrinology (58.2%), and ophthalmology/optometry (45.8%). A majority of subjects (72.8%) visited a primary care physician (PCP). Average number of office visits per-year was 4.8 for PCPs, 2.2 for endocrinologists, 1.5 for neurologists, and 0.6 for ophthalmologists/optometrists. Proportion with any all-cause and acromegaly-related healthcare utilization included 99.9% and 96.7% with an ambulatory visit, respectively, 48.6% and 6.8% with an emergency room visit, and 45.9% and 25.4% with an inpatient admission. Total all-cause healthcare costs (medical+pharmacy) averaged $2255/per-member-per-month. While pharmacy costs comprised 19.1% ($431/2255) of total costs, ambulatory and inpatient costs comprised the highest proportion of total medical costs, 48.1% ($877/1,825) and 44.7% ($815/1,825), respectively. Of total all-cause health care costs, 44.6% was for total acromegaly-related care ($1,005/2,255). Of total acromegaly-related medical costs, 63.3% ($498/787) was for acromegaly-related inpatient care. CONCLUSIONS  While acromegaly is generally under-diagnosed, subjects in this study had substantial health care utilization and costs for acromegaly-related care. Subjects visited a PCP most often, suggesting that substantial disease management was provided by physicians who may only treat a few acromegaly patients during their medical careers. Future studies focusing on treatment patterns prior to confirmed acromegaly diagnosis may increase awareness and expedite diagnosis of this condition in an earlier stage.