There is considerable suggestive evidence that parents can protect their adolescents from developing problem behaviors if they implement recommended best parenting practices. These include providing appropriate limits on adolescent free time, maintaining a close personal relationship with the adolescent, and negotiating and providing incentives for positive behavior patterns. However, retention of the study samples has limited conclusions that can be drawn from published studies. This randomized controlled trial recruited and randomized a national population sample of 1036 families to an intensive parenting intervention using telephone counseling or to a no-contact control group. At enrollment, eligible families had an eldest child between the ages of 10-13 years. The intervention included an initial training program using a self-help manual with telephone counselor support. Implementation of best parenting practices was encouraged using quarterly telephone contacts and a family management check-up questionnaire. A computer-assisted structured counseling protocol was used to aid parents who needed additional assistance to implement best practices. This, along with a centralized service, enabled implementation of quality control procedures. Assessment of problem behavior is undertaken with repeated telephone interviews of the target adolescents. The study is powered to test whether the intervention encouraging parents to maintain best parenting practices is associated with a reduction of 25% in the incidence of problem behaviors prior to age 18 years and will be tested through a maximum likelihood framework.