We report results of the studies relating to fabrication of an efficient immunosensor based on bismuth oxide nanorods (nBiO), electrophoretically deposited onto indium-tin-oxide (ITO) coated glass substrate. This immunosensor was fabricated by immobilization of anti-aflatoxin monoclonal antibodies (Ab-AFB1) and bovine serum albumin (BSA) for aflatoxin B1 detection. The structural and morphological studies of n-BiO have been carried out by XRD, UV-vis spectrophotometer; SEM, AFM and FTIR. It was found that the nBiO provided improved sensing characteristics to the electrode interface in terms of electroactive surface area, diffusion coefficient, charge transfer rate constant and electron transfer kinetics. The results of electrochemical response studies of this BSA/Ab-AFB1/nBiO/ITO immunosensor revealed good linearity in the range of 1-70ngdL with low detection limit of 8.715ng/dL, improved sensitivity of 1.132μA/(ng/dLcm), regression coefficient R of 0.918 and reproducibility of >11 times. The association constant for the BSA/Ab-AFB1/nBiO/ITO immunosensor was determined as 7.318ng/dL.