Zirconia nanoparticles embedded in amino functionalized amorphous carbon (nZrO(2)-NH2C) nanocomposite were synthesized by a novel, simple and one-pot hydrothermal method. The hydrothermal synthesis process involved carbonization of chitosan into amino functionalized amorphous carbon (NH2C) and simultaneously in situ growth of zirconia nanoparticles (nZrO(2)). The existence of carbon into the nanocomposite during the synthesis enhanced mechanical strength of nZrO(2). Beside this, the presence of NH2C in nanocomposite minimized the aggregation of nZrO(2) (similar to 10 nm), and hybrid interface of nZrO(2)-NH2C that enhanced the electro-chemical properties. The NH2C also improved the wettability of the nanocomposite as observed by contact angle measurement. This nZrO(2)-NH2C nanocomposite was deposited onto indium tin oxide (ITO) coated glass substrate using the electrophoretic technique. The oxygen moieties of nZrO(2) and amine groups of NH2C in nano composite formed an admirable microenvironment for immobilization of anti-OTA (antibodies specific to Ochratoxin A). XPS and FTIR studies revealed the presence of amine groups on nZrO(2)-NH2C nanocomposite and immobilization of biomolecules (anti-OTA and BSA) on its surface, respectively. The fabricated BSA/anti-OTA/ nZrO(2)-NH2C/ITO immunosensor revealed a selective detection of OTA in the detection range from 1 to 10 ng mL(-1) with a sensitivity of 0.86 ItA ng(-1) mL cm(2) and lower detection limit of 1 ng mL(-1).