Soybean oil-based composites are prepared by the solid freeforming fabrication (SFF) method. Epoxidized soybean oil is solidified with a gelling agent, and composites are formed by fiber reinforcement. Glass, carbon, and mineral fibers are used in the formulations. The type of fiber and degree of fiber alignments affect the properties of the composites. In addition, the effects of curing agents, curing temperature, fiber combination, and fiber loading on mechanical properties of composites and dynamic analysis are studied and reported.