Open molding is the method used in the polymer-matrix composites industry to make thermoset composite products. This article discusses the advantages, disadvantages, and applications of the open molding. It describes the various process of the open molding, such as hand lay-up process and spray-up process. Workmanship for hand lay-up and spray-up processes is reviewed. The article provides information on the matrix-resin materials used for open molding, including unsaturated polyester resins, epoxy vinyl ester resins, and reinforcements. It explains the component design and short- and long-term properties of a fiber reinforced composite laminate depending on material selection and workmanship. The article also presents the basic design guidelines for open molding.