The aim of this study was to compare the prevalence of osteoarthritis between adults with and without cerebral palsy. Data were collected from the 2016 Optum Clinformatics® Data Mart, a nationwide de-identified US insurance claims database, containing medical and pharmacy information on beneficiaries. International Classification of Diseases 10 th revision (ICD-10) codes were used to identify adults (age 18+ years) with and without cerebral palsy. ICD-10 codes were also used to identify osteoarthritis. Prevalence of osteoarthritis was compared between adults with (n = 7,348) and without (n = 8.7 million) cerebral palsy, before and after adjusting for age and sex. The results showed that adults with cerebral palsy had a higher prevalence and adjusted odds of any, poly, hip, knee, and other/unspecified osteoarthritis. Men and women with cerebral palsy had a higher prevalence of any osteoarthritis compared with men and women without cerebral palsy across all age groups. Adults with cerebral palsy had a higher prevalence of osteoarthritis compared with adults without cerebral palsy across the adult lifespan. Objective: Adults with cerebral palsy have an increased risk of developing osteoarthritis. However, little is known about the epidemiology of osteoarthritis among this vulnerable population. The objectives of this study were to compare the prevalence of osteoarthritis between adults with and without cerebral palsy, and to determine how the prevalence of osteoarthritis changes throughout adulthood for each group. Design: Data were extracted from the 2016 Optum Clinformatics® Data Mart, a nationwide database of de-identified US insurance claims, containing medical and pharmacy information on beneficiaries. Subjects: International Classification of Diseases 10 th revision (ICD-10) codes were used to identify adults (18+ years) with (n = 7,348) and without (n = 8.7 million) cerebral palsy. Methods: ICD-10 codes were used to identify osteoarthritis. Prevalence of osteoarthritis was compared between adults with and without cerebral palsy before and after adjusting for age and sex. The prevalence of any type of osteoarthritis was compared between men and women with and without cerebral palsy, stratified by the following age groups: 18-30, 31-40, 41-50, 51-60, 61-70, and > 70 years. Results: Adults with cerebral palsy had higher prevalence and adjusted odds of any, poly, hip, knee, and other/unspecified osteoarthritis (odds ratio (OR): 1.3-2.1; p < 0.001), but not hand osteoarthritis (OR: 0.86; p = 0.46). Men and women with cerebral palsy had a higher prevalence of any osteoarthritis compared with adults without cerebral palsy across all age groups (all p < 0.05). Conclusion: Privately-insured adults with cerebral palsy had a higher prevalence of osteoarthritis compared with adults without cerebral palsy across the adult lifespan.