The molecular imprinting technique was used in the synthesis of polymers having a high affinity for testosterone. These polymers thus function as receptor binding mimics for the drug. Various polymerization conditions were examined in order to determine their influence on the binding strength and selectivity of the binding mimics. Using a series of similar steroids, we were able to identify features of the molecules which affect their affinity for the polymer matrix. The efficacy of covalent and noncovalent imprinting methods was also compared. As determined by HPLC, the most selective (noncovalently imprinted) polymer bound testosterone over 4 times more strongly than did a nonimprinted polymer and at least 3 times more selectively than steroids of similar structure.