Comorbid conduct problems (CPs) and depression are observed far more often than expected by chance, which is perplexing given minimal symptom overlap. In this study, relations between parental psychopathology and children’s diagnostic status were evaluated to test competing theories of comorbidity. Participants included 180 families with an 8–12-year-old child diagnosed with CPs, depression, both conditions, or neither condition. Although no single theory of comorbidity was supported fully, evidence suggested that CPs and depression may be inherited separately. Paternal antisocial characteristics and maternal depression provided independent prediction of both child depression and CPs. However, paternal antisocial behavior moderated the effect of maternal depression on CPs. For children with antisocial fathers, CPs were observed regardless of maternal depression levels. In contrast, a strong relation was observed between CPs and maternal depression for children without antisocial fathers.