In this tutorial, we demonstrate how to use the Aggregate and Restructure procedures available in SPSS (versions 11 and up) to prepare data files for repeated-measures analyses. In the first two sections of the tutorial, we briefly describe the Aggregate and Restructure procedures. In the final section, we present an example in which the data from a fictional lexical decision task are prepared for analysis using a mixed-design ANOVA. The tutorial demonstrates that the presented method is the most efficient way to prepare data for repeated-measures analyses in SPSS.