In this study, a novel nonenzymatic sensor for the determination of hydrogen peroxide (H 2 O 2) was developed. The direct electrocatalytic oxidation of H 2 O 2 in an aqueous medium at a carbon-black (CB)-doped self-made polyimide (PI)-modified glassy carbon electrode (GCE) was investigated. The fabrication of this electrode is simple and reproducible. The filmlike surface was prepared by directly mixing the CB and PI solution. Under optimized conditions, the linear range of H 2 O 2 is from 6 to 10000 µM with the detection limit of 1 µM. The electrode exhibited high stability, excellent sensitivity, stable reproducibility, and fast response time (less than 5 s). The results show that PI can be used as a reliable and long-life sensor for hydrogen peroxide detection, exhibiting a new application for the PI.