Optimization of a chromatographic separation within the time constraints of a laboratory session is practically impossible. However, by employing a HPLC simulator, experiments can be designed that allow students to develop an appreciation of the complexities involved in optimization procedures. In the present exercise, a HPLC simulator from "JCE Software" is used to optimize the separation of a nine-component mixture. The relationship between solvent composition and retention factor is measured to determine the solvent composition for maximized separation. Use of Excel spreadsheets assists in the analysis of the data required for the optimization process. As a result, this exercise demonstrates the basics of the iterative process for optimization of separations and application of spreadsheets to solve relatively complex and tedious repetitive problems. (Contains 7 figures.)