Findings of a study that examined the effect of a computer-assisted absence registration system (ARS) on student truancy are presented in this paper. A pre- and post-test group design compared the truancy levels of 30 secondary schools in 4 large cities in western Holland who participated in the ARS program with those of 19 nonparticipating secondary schools. Other data were derived from interviews with and questionnaires filled out by teachers, principals, clerical staff, and the school ARS coordinator. Findings suggest that ARS did not significantly reduce absenteeism rates and that, after 20 months, the factors that influenced school motivation to use ARS and create a conducive school environment dissipated. No predictors were found for the development of antitruancy measures. Despite the system's failure to significantly reduce truancy, staff at the project schools reported some positive effects, such as time reduction, more efficient registration and handling of absences, and identification of attendance trends. One figure and seven tables are included. (Contains 11 references.) (LMI)