A uniform-sized molecularly imprinted polymer (MIP) for beta-estradiol has been prepared using 4-vinylpyridine and ethylenedimethacrylate as a functional monomer and cross-linker, respectively. The molecular recognition properties of the MIP were evaluated by HPLC using a mixture of phosphate buffer and acetonitrile as the eluent. The MIP showed the highest selectivity for beta-estradiol. The MIP could efficiently separate estrogens from other steroids such as testosterone and corticosterone, and could separate estrogens one another.