The voltammetric reduction behaviour of Doxepin (DXP) is utilized for its determination in pharmaceutical formulations and biological samples. The sepeolite modified carbon paste electrode (SMCPE) exhibited a significant increase in sensitivity and selectivity for DXP compared to bare carbon paste electrode (CPE). The effect of accumulation time, accumulation potential and pH of buffer solution on peak currents were studied. The peak currents were found to be linear over the concentration range of 4 x 10-8 to 5 x 10-7M and 3.6 x 10-9 to 4.2 x 10-8 M for CPE and SMCPE respectively. Differential pulse voltammetric method (DPV) and cyclic voltammetric method (CV) were developed for the determination of DXP in pharmaceutical formulations and biological samples.