Abstract Solid-state sensor for measuring antimony in molten non-ferrous metals is developed employing Na- β- Al 2 O 3 + NaSbO 3 composite solid electrolyte. The solid-state antimony sensor is schematically represented as M, Na ref // Na- β- Al 2 O 3 + NaSbO 3 // Sb melt, M. The antimony sensor has been tested in SnSb melt at 733 K, ZnSb melt at 793 K and CuSb melt at 1423 and 1473 K. The measurements were conducted in dilute alloys containing less than 1 wt% Sb. The antimony content of the alloy samples was analysed by AAS. The measured e.m.f. of antimony sensor was found to be Nernstian with a slope of − RT 3F when plotted against ln X sb.