This work uses a method that enhances the performance of glassy carbon electrode (GCE) for the determination of chloramphenicol (CAP). The electrochemical properties of chloramphenicol at electrochemically pretreated glassy carbon electrode were studied using cyclic voltammeter (CV). Electrochemical pretreatment of the electrode greatly enhanced the reduction peak current (Ip) of CAP. CAP shows an irreversible reduction peak at -0.674 V vs. Ag/AgCl at the GCE in 0.05 M acetate buffer of pH 5. Detailed experiments were carried out to establish the electrochemical property, the optimal buffer and its pH, electrode pretreatment potential, scan rate dependence study and effect of concentration. Following optimization pH of buffer solution, the peak current response for the reduction of CAP shows an enhanced response, 2.0 times greater than the bare GCE. A series of four CAP determination in 1.6 x 10-6 to 2 x 10-4 M concentration range show a linear calibration curve with r = 0.99997. At this range the limit of detection was LOD = 2.45 ?M with a standard deviation of SD = 0.03814. The method was successfully applied to three CAP containing pharmaceutical samples: CAP eye drop, CAP palmitat oral suspension and CAP as sodium succinate and the level of CAP in these samples was verified.