Melon-seed and rubber-seed oils have been used in the synthesis of polyester resins. Results reveal that rubber-seed oil can completely be substituted for linseed and soyabean oils in the synthesis of both long and medium-oil-length polyester resins. Melon-seed oil was found to be a substitute for 50% of linseed oil and 50% of soyabean oil in the synthesis of long-ail-length polyester resins. It also substituted for 15% of linseed oil and 50% of soyabean oil in the synthesis of medium-oil-length polyester resins. (C) 2000 John Wiley & Sons, Inc.