In this laboratory activity, students are introduced to a three-step synthesis of hydantoin (imidazolidine-2,4-dione), a moiety that is found in many biologically active compounds. Using a microwave oven and solid-support technology, this synthetic experiment is designed for masters-degree candidates working in organic chemistry or upper-level undergraduate chemistry students interested in solid-phase synthesis. A colorimetric test is used to monitor the reaction on the solid support and analytical techniques such as high-pressure liquid chromatography, mass spectrometry, and nuclear magnetic resonance are used to assess the product purity and yield. (Contains 1 table, 1 figure and 2 schemes.)