The main purpose of this study was to evaluate whether a research-based standardized parenting program could successfully improve the reciprocal interaction between parents and their young children. The program was implemented and evaluated with a 2-group (manualized parenting group; wait-list control group) repeated-measures design. It included pretest, post-test, and follow-up conditions, and a multi-measure assessment protocol. Thirty mothers and 10 fathers of children with behavior problems (ages= 3-5 years) participated in the parenting program. Results indicated a decrease in parental use of verbal and corporal punishment to their young children, and an increase of positive nurturing strategies, reduce parental stress, and improve parent perceptions of their child’s behavior. Children’s global pattern of behavior and psychosocial adaptation, as well as the observed parent-child interactions, also improved. Discussion focuses both on the effectiveness of using a manualized parenting intervention and on the relevance of parents’ stress and anger-aggression to improve our understanding of the reciprocal interaction between parents and their young children.