The System for Observing Fitness Instruction Time (SOFIT) is a direct observation system specifically developed for use during physical education (PE; McKenzie, 1991; McKenzie, Sallis, & Nader, 1991). The purpose of this study was to validate the estimates of time spent in various physical activity intensities obtained with the paper and pencil versions of the five-(McKenzie et al., 1991) and six-category (Pope et al., 2002) SOFIT scales during actual PE classes, using a computerized system of recording and timekeeping. This type of validation has traditionally been identified as concurrent validity. The authors hypothesized that there would be no difference between SOFIT paper and pencil estimates of time spent in various physical activity intensities and the actual time recorded in each activity intensity category. (Contains 1 table.)