This study presents the frequency of behavioral symptoms in 4− and 5-year-old children as reported by parents in the Ontario Child Health Study. It also examines the relationship of the presence of child, parent, and family variables with parent-reported total scale scores.Eight of the 135 items were reported to be present by the parents of 50% or more of the 437 children in the sample. For 18 items, the prevalence rates for boys were significantly higher than for girls. Multiple regression analysis resulted in slightly different child, parent, and family variables influencing scores when total scores and scores on severe items only were used as dependent variables. Two variables appeared in both models: general health of the child and family status. Some of the child, parent, and family variables found to be associated with behavior disorder in older children do not appear to have as strong an association with disorder in 4− and 5-year-olds.