The aim of the present study was to investigate pharmacokinetic profile and bioavailability of cyclooxygenase (COX)-2 selective nonsteroidal anti-infalmmatory drug nimesulide in bovine male calves after intravenous (i.v.) and intramuscular (i.m.) administration at a dose of 4.5mg/ kg BW. Blood samples were collected by jugular venipuncture at predetermined times following drug administration. Nimesulide in the plasma was assayed by using a validated HPTLC method. Plasma concentration-time data were subjected to compartmental analysis and pharmacokinetic parameters for nimesulide after i.v. and i.m. administration were calculated according to two and onecompartment open models, respectively. Following i.v. administration, a rapid distribution phase was followed by slower elimination phase. The half-lives during distribution phase (t1/2α) and terminal elimination phase (t1/2β) were 0.15±0.005h and 9.02±0.06h, respectively. The steady-state volume of distribution (vd(ss)), total body clearance (clB) and mean residence time (MRT) of nimesulide were 0.22±0.02L/h/kg, 0.02±0.001 and 11.23±0.04 h, respectively. After i.m administration, maximum plasma concentration (cmax) of nimesulide was 35.84±3.04 μg/ mL attained at 4.0±0.19 h (tmax). Plasma drug levels were not detectable upto 72h. Similarly the t1/2β (20.08±0.79h) MRT (13.76±0.09h) of nimesulide after i.m. administration were significantly longer than the i.v administration. The bioavailability of nimesulide was 89.42% after i.m administration. These pharmacokinetic data suggests that nimesulide given intramuscularly may be useful in the treatment of inflammatory disease conditions in bovines.