Three types of commercial cadmium-selective electrodes, Orion 94-48 A, Růžička Selectrode and TOA Cd-125, have been evaluated. Calibration curves were determined both in buffered and unbuffered cadmium ion solutions repeatedly during several weeks. Selectivities with respect to silver(I), copper(II), mercury(II), iron(II), iron(III), zinc(II) and lead(II), as well as the pH response, were determined by the mixed solution method. The response times of the electrodes were also studied.