Identified 3 subgroups of children from a prospective longitudinal study of temperament and development: (a) those with stable, (b) transient, or (c) no-behavior problems, as rated by mothers across the toddler, preschool, and preparatory school grade periods. Children with stable behavior problems were particularly characterized by more difficult temperament, mothers' overall perception of the child as difficult, and aggressive behavior in the 2- to 4-year age period. Group differences were linear rather than categorical with transient behavior problem children showing a lesser degree of difficulty. In a second study where more comprehensive child and family measures were available, temperament was again an important discriminator, with Vineland Adaptive Behavior Composite Score, mothers' overall perception of the child's temperament, and maternal psychological health and stress factors also more adverse for the stable group. However, correct classification of the members of these groups using a combination of the above variables was not impressive.