Arsenic (As) is considered to be one of the most toxic elements in water. Electrochemical techniques for the detection of As(III) have inherent advantages. In this study,- a series of electrochemical experiments were performed in order to detect the concentration of As (III) ions in aqueous phase via Anode Stripping Voltammetry (ASV) technique by using a Nafion-modified platinum electrode. The topology of the modified electrode was characterised with Atomic Force Microscopy (AFM). The electrochemical properties of the modified electrode were studied with ASV method and the optimisation parameters were determined: the amplitude of 0.02 V,- frequency of 25 Hz,- deposition time of 120 s. Under these optimised parameters,- the linear response was in the range from 0 ppb to 40 ppb with high accuracy (R2 = 0.9917). The responding time was approximately 150 s. The sensitivity of the modified Nafion/Pt electrode was 0.036 µA/ppb. The limit of detection was below 10 ppb which is approximately equal to the recommended level of World Health Organization (WHO). The results showed the possibility of using the modified Nafion/Pt electrode for the detection of As3+ in order to test the quality of domestic water. Copyright © 2020 Inderscience Enterprises Ltd.