This study assessed the 8-y stability and change of parent-reported problem behaviors in 791 children from the general population assessed at 2-y intervals with the same standardized procedure, the child behavior checklist (CBCL). Problem behaviors were rather stable across even the relatively long time interval of 8 y. The 8-y stability coefficient for total problem score was 0.48, with somewhat higher stability for externalizing than internalizing problems. Despite stability, problem behaviors also changed considerably across time. These changes do not only reflect the increase in chronologic age. The present study showed that there are changes in children's problem levels that result from historical time influences. These secular trends seemed of even greater importance than aging effects, and reflect a slight increase of the norm of children's problem behaviors.