AbstractBackground/aims: Studies have demonstrated that osteopontin (OPN) was associated with the severity and development of knee osteoarthritis (OA). Methods: The purpose of this case–control study was to investigate the association between OPN gene rs11730582 polymorphism and knee OA risk in a Chinese population. Genotyping was analyzed using standard PCR and restriction fragment length polymorphism (PCR-RFLP). Results: The present study found that C allele or CC genotype of OPN gene rs11730582 polymorphism was related to decreased risk for knee OA. Furthermore, positive associations were obtained amongst the females, and body mass index (BMI) < 25 kg/m2 groups. Conclusions: To sum up, the present study reveals that OPN gene rs11730582 polymorphism decreases the risk of knee OA in Chinese Han population.