We suggested a relationship between increased serum IMA (ischemia-modified albumin) levels and cartilage degeneration. We proposed that the increased serum levels of IMA was due to the oxidative stress mechanism against ongoing cartilage degeneration in osteoarthritis (OA) and thus may be associated with the progression of OA. We aimed to investigate serum IMA levels in OA patients and determine whether any changes in IMA levels are useful as a marker in increased OA.A prospective case-control study was carried out, which included 110 patients (55 patients with OA and 55 healthy controls). Serum samples obtained from all participants and IMA levels were determined by spectrophotometric method.Compared with controls, OA had significantly higher IMA and IMA/albumin (IMAR) levels (0.732 ± 0.078 vs. 0.773 ± 0.080, p = 0.008; 0.188 ± 0.20 vs. 0.176 ± 0.21; p = 0.011). Multivariable logistic regression analysis revealed rising IMA and IMAR levels were independently associated with OA (OR: 1.755, 95% CI: 0.655 - 4.700, p = 0.009 and OR = 3.021, 95% CI: 0.258 - 3.525, p = 0.015).The current study suggests that increased levels of IMA are associated with OA and are a probable predictive risk marker for the progression of OA.