The oxidative behavior of antibiotic roxithromycin standard was studied at a gold electrode in 0.05 M NaHCO3 using cyclic linear sweep voltammetry and differential pulse voltammetry. It was found that the value of the oxidative peak of pure roxithromycin at 0.81 V vs. SCE in 0.05 M NaHCO3 at a scan rate of 50 mV s(-1) is a linear function of the concentration in a range 0.10006-0.654 mg cm(-3). It was also found that peak current density at 0.75 V vs. SCE at a scan rate of 2 mVs(-1), pulse amplitude of 25 mV and pulse time of 0.1 s exhibits linear dependence on the concentration of roxithromycin from 0.1006 to 0.476 mg cm(-3). Roxithromycin as a content of solid dosage form and urine was quantitatively determined and the obtained results were checked by HPLC. (C) 2010 Elsevier Ltd. All rights reserved.