Objective: To examine the role of parental diabetes mellitus (DM) in the development of type 2 DM among children and adolescents from high-risk ethnic groups. Study design: A population-based dataset of insulin-treated diabetes among African American and Latino children <18 years old yielded 243 cases who completed an inter-view. A subset with features of type 2 DM was identified (n = 44) using one or more criteria: stopping insulin therapy; using oral hypoglycemic agents; acanthosis nigricans; polycystic ovary syndrome; denoted "atypical" or "type 2" by a physician. Results: Of all the patients, 76% had no known diabetic parent; 7% had father only; 15% had mother only; and 2.5% had two diabetic parents. Parental DM was more likely in type 2 than in type I children (only paternal, 15.9% vs 5.5%, P < .02; only maternal, 38.6% vs 9.5%, P < .01; or both, 6.8% vs 1.5%, P < .01). Conclusion: A positive parental history of DM appears to be more strongly related to childhood type 2 than to type I DM. Whether this is a reflection of genetic or behavioral factors is yet unclear.