Abstract: Flexible castor oil-based polyurethane foams were produced by the one-shot method of foam synthesis. Foam formulation involved pure castor oil/castor oil modified with heptachloroheptadecane (HCHD), a novel C-17 chlorinated hydrocarbon internal plasticizer, 80:20 mixture of 2,4 - and 2,6 - toluene diisocyanate (TDI) at room temperature (30 - 350C). Foam reaction took place in presence of stannous octoate and dimethylaminoethanol (DMAE) catalysts, methylene chloride (physical blowing agent) and silicone oil (surfactant).