The pharmacokinetics and dosage regimen of cefotaxime following its single subcutaneous administration (10 mg/kg) were investigated in buffalo calves. Plasma and urine samples were collected over 10 and 24 h post administration, respectively. Cefotaxime in plasma and urine was estimated by microbiological assay technique using E. coli as test organism. The pharmacokinetic profiles fitted one-compartment open model. The peak plasma levels of cefotaxime were 6.48 +/- 0.52 microgram/ml at 30 min and the drug was detected upto 10 h. The absorption half-life and elimination halflife were 0.173 +/- 0.033 h and 1.77 +/- 0.02 h, respectively. The apparent volume of distribution and total body clearance were 1.17 +/- 0.10 l/kg and 0.45 +/- 0.03 l/kg/h, respectively. The urinary excretion of cefotaxime in 24 h, was 5.36 +/- 1.19 percent of total administrated dose. A satisfactory subcutaneous dosage regimen for cefotaxime in buffalo calves would be 13 mg/kg repeated at 12 h intervals.