Carbamylcholine (M) modified paraffin-impregnated graphite electrode (CCh/WGE) was prepared and characterized by using X-ray photoelectron spectroscopy, UV-vis spetroelectrochemistry and cyclic voltammetry. It was found that the CCh/WGE could be used for surface accumulation and electrocatalytic determination of estrogens involving estradiol, estrone and estriol. By using square-wave stripping voltammetry, an anodic peak was observed at about 0.55 V versus SCE for all these estrogens. The peak current was proportional to concentration of estradiol, estrone and estriol in the range from 4 x 10(-6) to 4 x 10(-5), 3 x 10(-7) to 3 x 10(-5), and 5 x 10(-7) to 9 X 10(-6) M, respectively. This electrode could be used for determination of estrogens in practical samples. © 2005 Elsevier Ltd. All rights reserved.