 This paper presents a simple, inexpensive, and highly sensitive electrochemical sensor based on new polymeric membrane incorporating kinetin (6-furfurylaminopurine) as a specific sensitive molecule deposited on the surface of a glassy carbon electrode for the detection of cadmium in water. The electrochemical characterization was examined using electrochemical impedance spectroscopy and cyclic voltammetry. Additive effect and selectivity for cadmium over many common cations, such as copper, lead, and zinc, at pH 4.5 are studied. We showed that the cadmium selectivity is better for membrane based on potassium tetrakis(4-chlorophenyl)borate (KTpClPB) with a significant decrease of the Rct and an increase in constant phase element CPE, the sensor exhibits a LOD of 3.96 × 10–10 M with a linear response towards cadmium ions over a wide concentration range of 10–6 to 10–9 M. Finally, the proposed sensor was applied to the determination of cadmium in water and can be proposed to use successfully in real water samples.