A new method allowing the analysis of inorganic arsenic species using isotachophoresis has been developed. This method has been shown to be suitable for use on both miniaturised planar polymer separation devices and capillary scale devices. A poly(methyl methacrylate) chip with integrated conductivity electrodes has been successfully used for the rapid analysis of inorganic arsenic species in under 600 s. Limits of detection of 1.8 mg l−1 and 4.8 mg l−1 for arsenic(V) and arsenic(III), respectively, have been achieved with the miniaturised device. The device has also been used to perform the simultaneous separation of arsenic(III), arsenic(V), antimony(III), molybdenum(VI) and tellurium(IV).