Male Wistar rats were injected intraperitoneally with 40 mg/kg of 14C-sulfinpyrazone. The drug was rapidly absorbed and its half-life in the blood was 16.2 h. Most of the radioactivity was excreted in the bile. Sixty-eight percent of the dose appeared in the feces and 18% in the urine in the first 72 h. A considerable portion of the radioactivity excreted in bile was reabsorbed in the intestinal tract. One metabolite, p-hydroxysulfinpyrazone, was found in urine, bile, and feces. Previous results have shown sulfinpyrazone to be a uricosuric in man. It is excreted quickly, both as the parent drug and its hydroxy metabolite, in human urine. The failure of the rat to excrete a high percentage of the drug in the urine may be related to its lack of uricosuric properties in this species.