Enrofloxacin was given to elinically healty six holstein dairy cows ata dosage of 2,5 mg/kg of body weight by IM as only dose. Milk samples were taken from cows 24th, 48th, 72th, 96th and 120th hours after drug administration and before administration. Residues of enrofloxacin were determined in milk samples by HPLC method. Determined means concentrations of enrofloxacin in milk samles were respectively 0.035 ± 0. 005, 0. 025 ± 0.009, 0.0054± 0.003 mcg/ml at 24th, 48th and 72th hours. Enrofloxacin was not determined in milk samples at 96th and 120th hours.