This study evaluated the effects of a brief 3- to 4-session behavioral family intervention program for parents of preschool-aged children in a primary care setting, compared to parents in a wait-list control condition. Parents receiving the Primary Care Triple P-Positive Parenting Program intervention reported significantly lower levels of targeted child behavior problems, dysfunctional parenting, and reduced parental anxiety and stress in comparison to wait-listed parents at postassessment. These short-term effects were largely maintained at 6-month follow-up assessment of the intervention group. Implications of these findings for the prevention of behavioral and emotional problems in children are discussed. (Contains 3 tables.)