In the absence of polymerization, soy-based polyols tend to have inadequate hydroxyl equivalent molecular weights for many critical urethane applications. In this article, the polymerization (bodying) of soybean oil is presented as in effective method to increase the molecular weight of soy-based polyols. When bodying is combined with reaction steps for alcohol addition and acid reduction, soy-based polyols Suitable for urethane applications can be synthesized. Two different heat-polymerization approaches, catalyzed- and noncatalyzed-bodied soybean oil (BSBO) were calculated in continuous and batch processing. The catalyzed-BSBO has lower iodine numbers and high viscosities than the noncatalyzed-BSBO. This approach represents one of the least-costly means to increase the hydroxyl equivalent weights of soy-based polyols. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 212-2135, 2009