The Pharmacokinetics of florfenicol was studied in buffalo calves following single intravenous and intramuscular administration of 20 mg kg-1 b.wt. Florfenicol concentration in both serum and urine were determined by microbiological assay using Bacillus subtilis (ATCC 6633) as test organism. After intravenous injection the serum florfenicol concentration time course obeys two-compartment open model with distribution (t0.5 (
)) and elimination (t0.5 ()) half lives of 0.381 ± 0.004 and 2.89 + 0.263 h., respectively. Total body clearance (CLB) and steady state volume of distribution (Vdss) were 3.6 ± 0.30 ml kg-1 min-1 and 1.70 ± 0.010 l kg-1., respectively. After intramuscular administration the observed mean peak serum concentration (Cmax) was 2.32 ± 0.052 3g ml-1 achieved after maximum time (Tmax) of one hour postinjection. The systemic bioavailability after intramuscular administration was 27.43 % and the plasma protein binding was 13.5 %.