Background: Data on the economic consequences of hip and knee osteoarthritis (OA) are scarce. We aimed to estimate the annual direct and indirect costs for patients followed for hip and/or knee OA in the Knee and Hip Osteoarthritis Long term Assessment (KHOALA) cohort. Methods: The KHOALA cohort, set up from 2007 to 2009, is a French multicenter study of 878 individuals with symptomatic knee/hip OA who were 40e75 years old. Resources used were collected annually for 5 years. Costs were assigned by using official sources and expressed in 2018 euros per patient. Results: The mean annual total costs per patient over the 5-year study period were 2,180 ± 5,305V. The mean annual direct medical costs per patient were 2,120 ± 5,275V and mean annual indirect costs per patient 180 ± 1,735V for people of working age. Costs increased slightly over the study period. Drugs were the largest cost share, representing over 50% of all direct costs. However, the proportion attributable to OA drugs accounted for only 10.5% of drug costs. The second cost share was hospitalizations; hip and knee prosthetic surgery accounted for 27% of surgery hospitalization costs. Health professional visits were the third cost share, accounting for 3% of direct medical costs. The median costs induced could be as high as 2 billion V/year (IQR 0.7e4.3) in France. Conclusion: Hip and knee OA costs were substantial and increased over the study period in France. However, the costs attributable to OA represented only a small fraction of overall costs.