〔Abstract〕 Objective To investigate the effects of adjuvant arthritis(AA) on renal function and the expression of organic anion transporter 3(OAT3) in rats. Methods The AA model was establishedviaintradermal injection of Freund′s complete adjuvant into the right hind toe of the rats. Blood and urine were collected at fixed time points to observe the dynamic changes of renal injury indicators. The kidney injury was observed by HE staining. Immunohistochemistry and Western blot were used to detect the expression levels of OAT3 protein and inflammatory factors interleukin-6(IL-6), interleukin-1β(IL-1β) and tumor necrosis factor-α(TNF-α) in renal cortex. Results Compared with the normal group, the arthritis index score, the secondary paw swelling, the number of joint swelling, and the whole body score of AA rats significantly increased(P<0.05). The X-ray results showed that the AA model rats had soft tissue edema and bone deformity. Biochemical indicators showed that the renal injury indicators of AA rats were significantly abnormal. The results of immunohistochemistry and Western blot showed that the expression level of OAT3 in renal cortex of AA rats significantly decreased, while the expression levels of inflammatory factors IL-6, TNF-α and IL-1β significantly increased(P<0.05). Conclusion The renal injury of AA rats may be related to the decreased expression level of OAT3 and the increased expression level of inflammatory factors in kidney.