This paper reports, for the first time, the fabrication and characterization of highly sensitive and selective electrochemical sensor for the efficient detection of cadmium ion using SnO2 quantum dots (QDs). The SnO2 QDs were prepared by simple and facile low-temperature hydrothermal process and characterized by several techniques. The detailed characterizations revealed that the QDs are pure SnO2, prepared in large quantity with the average size of 2-4 nm and possessing well-crystallinity with tetragonal crystal structure. Further, the prepared SnO2 QDs were used as potential scaffold to fabricate highly sensitive, selective and reproducible electrochemical sensor for the efficient detection of cadmium ions. The fabricated sensor exhibited a high sensitivity of similar to 77.5 x 10(2) nA ppm (1) cm (2), a low detection limit of similar to 0.5 ppm and response time of <2s. The presented work demonstrates that the SnO2 QDs are effective electron mediators to fabricated efficient electrochemical sensor for the easy, cost effective and accurate on-site detection of cadmium ions in solution. (C) 2015 Elsevier Ltd. All rights reserved.