The effect of etodolac 50-600 mg/d on renal function was assessed in four- to 52-week trials in 1,382 patients with arthritides. No patient was withdrawn from treatment due to an abnormal renal function test related to etodolac administration. There were no significant differences in the incidence of definite renal function abnormalities between patients receiving etodolac and those receiving placebo. Both etodolac and placebo groups had a significantly lower incidence of deviant BUN results than either aspirin- or sulindac-treated patients. Fewer than 2% of patients receiving etodolac showed either a persistent or variably persistent pattern of deviant renal function tests. The results in these studies indicate that chronic etodolac therapy did not adversely affect renal function in patients with arthritis.