Flexible modular scheduling (flex mod)--a schedule philosophy and system that has been in place at Wausau West High School in Wausau, Wisconsin, for the last 35 years and aligns nicely with current research on student learning--is getting more and more attention from high school administrators across the country. Flexible modular scheduling was introduced in the late 1960s and grew in popularity with the advent of more-sophisticated computer programs that could facilitate complex scheduling, and only a handful of secondary schools still use it today. The reasons for its decline are varied, but some theorize that limited resources, the complexities of managing a flex mod schedule, and such scheduling alternatives as the block schedule all played a role. Flex mod is built on the belief that instruction and learning can be best accomplished by adjusting class times and structure to meet designated instructional goals. In many high schools, the day is divided into seven or eight periods that typically run for about 50 minutes. In other schools, the day is divided up into four periods of approximately 90 minutes each. At Wausau West the day is divided into 21 periods. These periods are called "mods," and each mod lasts for 20 minutes. This simple division of the day may not seem that significant, but the instructional implications of such a schedule and the philosophy that goes with it are substantial. Flex mod scheduling prepares students for life after high school and takes the individual needs of each student into consideration. The system gives young people the chance to learn to manage their time and their learning by choosing where to spend their unstructured time, working cooperatively with other students in small group settings, and working with adults in various environments. The system provides opportunities for curious students to take extra classes to explore unique interests, for career-minded students to take advantage of career center resources and job training opportunities, for college-bound students to take advanced courses, and for late-maturing students to catch up on needed credits. Flex mod is not a perfect system, and it will probably not work in schools that are missing some basic philosophical and material supports that are needed for its success. In the right setting with the right staff, however, and in combination with other sound, research-based instructional practices, the benefits of flex mod can be significant. (Contains 1 figure.)