In this study, the effect of doramectin, moxidectin and netobimin was investigated in naturally infected Syphacia muris in rats. The natural infection was determined by the use of cellophane tape method on the perianal region and by the technique of centrifugal flotation of feces. The infected rats were divided into three treated and one control group (N = 10), Doramectin and moxidectin at the dose of 0.2 mg/kg per day and netobimin at the dose of 7.5 mg/kg per day were given in the diet for 4 days. Cellophane tape preparations were performed in all groups on 4th and 7th day after the last treatment. The rats of treated groups were necropsied on 7th day after the last treatment together with that of control group. While doramectin and netobimin were highly effective against S. muris, moxidectin was not found to be effective for eradication of S. muris; (C) 2000 Elsevier Science B.V. All rights reserved.