Objective: We examined the relative contribution of parental bipolar disorder (BPD) and psychiatric comorbidities (disruptive behavior disorders [DBD] and anxiety disorders) in predicting psychiatric symptoms and disorders in 2-5-year-old offspring. Methods: Participants were 60 families with a parent with BPD and 78 offspring and 70 comparison families in which neither parent had a mood disorder and 91 offspring. Parent and offspring diagnoses and symptoms were assessed using standardized diagnostic interviews and measures, with offspring assessors masked to parental diagnoses. Results: Offspring of parents with BPD had significant elevations in behavioral, mood and anxiety disorders and symptoms. Both parental BPD and DBD contributed to elevations in child disruptive behavioral symptoms, whereas child anxiety symptoms were more strongly predicted by comorbid parental anxiety. Parental BPD was a stronger predictor than comorbid DBD of child DBDs. Conclusion: Some of the elevated risk for disorders in preschoolers is accounted for by parental comorbidity.