The pharmacokinetics of ibuprofen were studied in four nephrectomized and three normal dogs after administration of 214.3–227.6 mg iv of ibuprofen. Blood samples were collected at various time intervals for up to 10 h and serum concentrations of ibuprofen were assayed by an HPLC method. The elimination of serum ibuprofen followed first-order kinetics, with mean half-lives of 2.51 ± 1.10 and 2.81 ± 0.72 h in normal and nephrectomized dogs, respectively. Mean serum clearance of ibuprofen in nephrectomized dogs, 31.0 ± 5.2 mL/h/kg, was higher than that in normal dogs, 12.2 ± 8.6 mL/h/kg, (p < 0.02). The difference may be attributed to the greater volume of distribution for ibuprofen in nephrectomized dogs, 125.2 ± 39.0 (88.8–160.4) mL/kg as compared with 53.4 ± 57.8 (26.0–119.9) mL/kg in the normal group (p < 0.2).