Molecular docking is a frequently used method in structure-based rational drug design. It is used for evaluating the complex formation of small ligands with large biomolecules, predicting the strength of the bonding forces and finding the best geometrical arrangements. The major goal of this advanced undergraduate biochemistry laboratory exercise is to illustrate the importance and application of this tool. Students carry out the computational modeling of the interaction of acetylcholinesterase and its inhibitor, tacrine, and learn about the concepts of protein structure, enzyme-inhibitor interactions, intermolecular forces, and role of molecular design in drug-development. (Contains 4 figures and 1 table.)