We evaluated the prevalence of acanthosis nigricans among urban youth. Youth (7-17 years) at nine pediatric practices completed surveys on demographics and family history of diabetes and had weight and height measured. Acanthosis nigricans was scored and digital photography of the neck performed. A total of 618 youth were included in the analysis: mean age 11.5 years; 51% female; 61% African American, 27% Hispanic, 12% Caucasian, and 32% with body mass index >or=95th percentile. Acanthosis was found in 19%, 23%, and 4% of the African American, Hispanic, and Caucasian youth, respectively, and in 62% of youth with a body mass index >or=98 th percentile. Using multiple logistic regression, we found increasing body mass index z-score, presence of maternal gestational diabetes, female gender, and not being Caucasian each were independently associated with acanthosis nigricans. Acanthosis was common among overweight youth and was associated with risk factors for glucose homeostasis abnormalities. Acanthosis nigricans can be a trigger to counsel families on its causes and consequences; and thus motivate them to make healthy lifestyle changes that can decrease the risk of developing cardiovascular disease or diabetes.