Oxidation of sulfanilamide (SN) at the Glassy Carbon Electrode (GCE) modified with a thin layer of electropolymerized Eriochrome Black-T (EBT) and multi walled carbon nanotubes (MWCNT) was investigated voltammetrically. The performance of layer by layer modified composite electrode was compared with bare GCE, p(EBT)/GCE, and MWCNT/GCE using cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). An enhanced current response and lower peak potential were observed for SN oxidation at the layered composite electrode compared to rest of the electrodes. Hence, it was employed for analytical determination of SN after optimization of experimental parameters. Under optimized condition, the oxidation peak current increased linearly with concentration of SN over the range of 2 Χ10^-8 to 5 Χ 10^-6 M. The limit of detection was calculated to be 1.2 Χ 10^-8 M. The electrode showed good selectivity, repeatability and reproducibility. It was also successfully applied for the determination of SN present in spiked human serum and ground water samples.