Relatively few studies have examined the continuity of preschool emotional and behavioral problems. Existing studies have typically focused on externalizing problems, included checklist measures that provided few details about symptoms, and used clinical samples that are subject to a variety of biases. Longitudinal studies are needed to elucidate the clinical significance and future implications of psychopathology in young children. This prospective study examined the stability of psychopathology in a large (N = 462) community sample of young children using a comprehensive diagnostic interview with parents. Specific emotional and behavioral symptoms were assessed at ages 3 and 6, and child, familial, and life stress variables were examined using multi-method assessment as possible predictors of continuity. The overall rates of disorders, level of comorbidity, and pattern of symptom covariation were relatively stable from age 3 to age 6. Rates of depression and attention-deficit hyperactivity disorder (ADHD) increased from age 3 to 6, whereas rates of generalized anxiety disorder (GAD) decreased. There was significant homotypic continuity between age 3 and age 6 for anxiety, ADHD, and oppositional defiant disorder (ODD), and heterotypic continuity between depression and anxiety, anxiety and ODD, and ADHD and ODD. Age 3 anxiety, maternal depression and anxiety, and early stressors predicted an increase in depressive symptoms from age 3 to age 6. Age 3 ODD, child temperamental dysphoria, and maternal anxiety predicted an increase in anxiety symptoms. Finally, early stressors predicted an increase in ODD symptoms. In addition, there was a significant linear association between the sum of predictors present and an increase in levels of symptoms, suggesting that risk accumulates to predict a worse course of psychopathology. This study supports the validity of emotional and behavioral problems in preschoolers and contributes to our understanding of the course and clinical significance of psychopathology in young children. These findings should encourage the continued development of prevention and early intervention efforts targeting both emotional and behavioral problems and their developmental sequelae.