The purpose of this study is to examine the effectiveness of an in-home parent management program for toddlers with behavior problems and developmental delays by comparing outcomes for a group of toddlers with developmental delays (n = 27) and a group of toddlers without developmental delays (n = 27). The majority of children lived in single parent, low-income homes. Results suggest that the parent management program is equally effective for children with and without developmental delays. Parents from both groups reported clinically significant improvement in their children's behavior and parenting practices. Clinical implications regarding the importance of these findings for improving outcomes for toddlers with behavior problems and developmental delays living in poverty were discussed.