Importance: Health care providers' knowledge of and comfort working with adults with developmental disabilities (DD) affect the quality of care this growing population receives. Previous research on this topic has not included occupational therapy practitioners. Objective: To determine occupational therapy practitioners' views about working with older adults with DD in traditional health care settings. Design: Quantitative survey over 4 mo. Participants: A random sample of 310 practitioners from the American Occupational Therapy Association's Gerontology and Physical Disabilities Special Interest Sections working in traditional health care settings. Outcomes and Measures: A researcher-developed survey to assess occupational therapy practitioners' comfort, knowledge, challenge, and supports and barriers in regard to working with older adults with DD. Results: In the 310 included surveys (31% response rate), most occupational therapy practitioners reported feeling comfortable (76.1%-80.0%) and knowledgeable (66.5%-68.4%) working with older adults with DD. Approximately 93% reported that work with older adults with DD was at least somewhat challenging. Key perceived barriers included clients' cognitive needs, lack of caregiver collaboration, and challenging behavior. Conclusion and Relevance: Most occupational therapy practitioners in traditional health care settings found working with older adults with DD challenging, and many did not feel sufficiently knowledgeable to meet the needs of this population. Similar to other health professionals, occupational therapy practitioners may benefit from additional resources to provide services to this population.