Poly(Eriochrome black T) film was electrodeposited onto glassy carbon electrode. The formation mechanism of the polymer film was explored. The as-prepared film showed good affinity to nitric oxide, and the oxidation process of nitric oxide at the film electrode was proposed. A novel nitric oxide sensor was developed based on this film electrode. The influence of the preparing conditions on the sensing performance of the film electrode was discussed. The proposed sensor was used to monitor NO release from the rat heart homogenate by the addition of L-Arginine, and the current responses enhanced. (C) 2008 Elsevier Ltd. All rights reserved.