The potential use of castor oil in preparation of novel biodegradable polymeric pressure sensitive adhesives and fiber reinforced polyester composites was investigated. A biodegradable oligomeric fumarated resin was prepared by the insitu hydroxylation of castor oil followed by maleation under controlled reaction conditions. Then two varieties of biodegradable pressure sensitive adhesives (PSAs) were prepared by further reacting the resin with co-monomers vinyl acetate and methyl acrylate. The PSAs were characterized for biological and physicochemical properties; namely thermal stability, transparency, chemical resistance, biodegradability, and tensile strength. Fiber reinforced polyester composites were prepared by free radical polymerization of oligomeric fumarated resin mixed with different propositions of Jute and Sisal fiber. The composites were then analyzed for physicochemical by AT-IR, SEM, TGA and DSC techniques, The results indicate that castor oil-based PSA films and tapes have applications in various fields including flexible electronics and medical devices because of their thermal stability, transparency, chemical resistance, and potential biodegradability from triglycerides. Mechanical characterization of the composites was also done and the results positively indicated the Sisal and Jute fibers have the potential to be used as substitutes for synthetic fibers in green composites. The composites can be used for the fabrication of eco-friendly materials.