Open-tubular capillary electrochromatography (OT-CEC) with a new stationary phase, O-cynaoethyl chitosan, has been applied to the separation of four cephalosporins. Several experimental parameters such as the buffer type, pH and buffer concentration, mobile phase composition, and applied voltage were evaluated. Baseline resolution of the studied cephalosporins could be achieved within 14 min. The calibration curves of cefixime, cephalothin, cefuroxime, and cefoperazone were linear over the concentration range of 0.6-50, 0.8-50, 0.8-50, and 1.0-50 mu g/mL, respectively. The detection limits (S/N = 3) of four cephalosporins ranged from 0.2 to 0.4 mu g/mL and the recoveries of the milk samples were about 82.0-96.7% (RSD <= 3.8%).