Background: Adults with Autism Spectrum Disorder (ASD) encounter many difficulties finding and accessing health care services. Despite this, few studies have considered the health service use patterns of adults with ASD without intellectual disability (ID). Objectives: The current study examines a diverse range of medical and mental health services and supports, as well as adults' personal experiences accessing and using these services, barriers to service use, and reported unmet service needs. Methods: Forty adults (ages 18-61 years) with ASD without ID completed surveys every two months about their health service use for a total of 12-18 months. Bivariate analyses were conducted to understand the individual demographic and clinical factors associated with rate of service use, satisfaction with services, and barriers to health care. Results: Results indicated that, beyond a family doctor, the most commonly used services were dentistry, individual counseling, and psychiatry. Individuals who had medical problems experienced significantly more barriers to service use than those who did not, and those who had medical and mental health problems were less satisfied with services. Conclusions: Findings highlight the challenges adults with ASD without ID face accessing appropriate, quality services to meet their needs, particularly those with complex medical and mental health issues. Service providers must strive to provide adequate health care to this population who may become distressed if their needs are left unmet. (C) 2016 Elsevier Inc. All rights reserved.