Objective To evaluate whether hip osteoarthritis (OA) is a risk factor for checkpoint inhibitor-induced inflammatory arthritis (ICI-IA). Methods Patients treated for thoracic cancers with ICI therapy and with a CT of the abdomen/pelvis within one month of ICI start were included; hip OA was graded from a coronal slice of the CT by a radiologist. Chart review determined the presence of ICI-IA and other immune related adverse events Those with Kellgren-Lawrence grade of 2 or higher in either hip on CT abdomen/pelvis were classified as having hip OA. Incidence rates of ICI-IA were calculated in patients with and without hip OA. Development of ICIIA and overall survival were compared by Kaplan-Meier curves and Cox proportional hazards. Results A total of 309 patients were included; 103 had hip OA on CT scan. Overall, the cumulative incidence of ICI-IA was 54.8/1000 person-years and did not significantly differ between those with and without hip OA (p=0.78). In the Cox proportional hazards model for ICI-IA development, hip OA was not associated with ICI-IA development (HR 1.24, p=0.55), but higher BMI was associated with a significantly lower hazard for ICI-IA (HR 0.93, p=0.049). Survival did not differ by hip OA status but was improved in patients with ICI-IA (HR 0.59, p=0.02) and higher BMI (HR 0.97, p=0.03) and worsened in higher cancer stage (HR 1.61, p=0.003) in the multivariable analysis. Conclusion CT-derived Hip OA was not significantly associated with development of ICI-IA in this cohort of lung cancer patients. ICI-IA was associated with decreased mortality.