A novel sensor based on carbon black-gold nanoparticle nanocomposite modified screen-printed electrode (CB-AuNPs/SPE) for the detection of As(III) has been developed. The sensor was prepared modifying the SPE with CB and AuNPs by a drop casting automatable deposition. The As(III) was detected by CB-AuNPs/SPE using anodic stripping voltammetry, with a high sensitivity (673±6 µA µM−1 cm−2) and reaching a LOD of 0.4 ppb. Finally, CB-AuNPs/SPE has been applied to As(III) trace analysis in drinking water, obtaining satisfactory recovery values (99±9 %).