The study found that children with a family history of depression were at increased risk for developing depressive symptoms in an environment of family conflict. This suggests that interventions designed to prevent or mitigate the emergence of depressive symptoms in children and youth with a family history of depression should focus on family interactions and how they might aggravate or reduce genetically based vulnerability to depression in children and youth. A sample of families from the Cardiff Study of All-Wales and Northwest of England Twins was invited to participate in the current study. These families were selected from a population-based register of twin births between 1980 and 1991. At the first wave of data collection in 1997, data were collected through a mailed questionnaire that was completed for 2,082 twins ages 5 to 16. Three years later, data were obtained for 934 of the twin pairs. The conflict subscale of the Family Environment Scale was used to assess family conflict, and the Mood and Feelings Questionnaire was used to assess depressive symptoms. For younger children, their mothers reported on their depressive symptoms. 3 tables, 2 figures, and 47 references