A continuous pilot plant process for converting lactose to lactulose, using boric acid as a complexation agent was previously developed. To appraise the commercial feasibility of the process, a scale-up to a commercial plant using the ERRC Food Process Simulator, a process simulator developed at the Eastern Regional Research Center was projected and a cost estimate made. The cost to produce a 55% lactulose syrup at a rate of 93 kilograms per hour (563 359 kg year(-1)) was $5.20 per kilogram ($2.36 per pound). These costs, which do not include packaging or distribution expenses, do include a 25% return on the plant investment.