OBJECTIVE: To examine the stability of the occurrence of psychiatric disorders in a nonpsychiatric sample of young children. METHOD: There were 510 children ages 2-5 years enrolled through pediatric practices, with 391 children participating in the second wave, and 344 in the third wave of data collection 42-48 months later. The assessment battery administered at each wave yielded best-estimate consensus DSM-III-R diagnoses and dimensional assessments of psychopathology. RESULTS: The prevalence of disruptive disorders (DDs) decreased, while emotional disorders (EDs), other disorders, and comorbid DD increased. The DDs were associated with lower family cohesion, more maternal negative affect, stressful life events, and male gender. Comorbid DDs were associated with increasing age and family cohesion. Older children, lower family cohesion, and maternal negative affect were associated with EDs. Time trends for the dimensional assessment of psychopathology was similar to DSM-III-R disorders, but correlates differed. CONCLUSIONS: We discuss implications for service planning in pediatric primary care.