BACKGROUND: Studies have suggested an association between the presence of acanthosis nigricans (AN) and the development of diabetes. OBJECTIVE: To investigate the association between AN and insulin resistance (IR) in overweight children and adolescents receiving care at the Center for Childhood Obesity, Campina Grande, PB. METHODS: This cross-sectional study was conducted between April 2009 and April 2010 including 194 individuals of 2 to 18 years of age receiving care within the Brazilian national health network. The presence of acanthosis nigricans was verified and anthropometric measurements were taken. The following tests were performed: insulin, triglycerides, HDL-cholesterol, glucose and homeostasis model of assessment -insulin resistance (HOMA-IR). Statistical analyses were performed using the SPSS software program, version 17.0. RESULTS: There was a greater prevalence of females (66%), brown-skinned individuals (63.4%), adolescents (61.3%) and severely obese individuals (66.5%). Acanthosis nigricans was identified in 58.2% and IR in 42.7% of the participants. Acanthosis nigricans was associated with being non-white (p = 0.003), with being an adolescent (p = 0.003) and with IR (p = 0.001). Non-white individuals, adolescents and those with insulin resistance were 5.4, 2.47 and 2.66 times more likely to have acanthosis nigricans, respectively. CONCLUSION: The results of this study indicate a need to train healthcare professionals to identify acanthosis nigricans, since this condition is associated with IR. Identifying acanthosis nigricans in childhood permits the safe and timely treatment of cardiometabolic disorders through careful monitoring and appropriate treatment. Keywords: Acanthosis Nigricans; Adolescent; Child; Insulin Resistance Resumo: FUNDAMENTOS: Estudos sugerem haver associação entre a presença de Acantose Nigricans e o desenvolvimento do diabetes. OBJETIVO: Verificar a associação entre Acantose Nigricans e Resistência Insulínica (RI) em crianças e adolescentes com excesso de peso, atendidos no Centro de Obesidade Infantil, Campina Grande-PB. MÉTODOS: Estudo transversal realizado entre abril/2009 a abril/2010, com amostra de 194 pessoas entre 2 e 18 anos, usuários do Sistema Único de Saúde. Na avaliação, foi observada a presença de AN e verificadas as medidas antropométricas. Foram realizados os exames: insulina, triglicerídeos, HDL-colesterol, glicose e HOMA-IR. As análises estatísticas foram realizadas no SPSS, 17.0. RESULTADOS: Houve maior prevalência do sexo feminino (66%), pardos (63,4%), adolescentes (61,3%) e obesos graves (66,5%). Foi identificada AN em 58,2% e RI em 42,7%. A Acantose Nigricans esteve associada à cor não-branca (p=0,003), adolescentes (p=0,003) e RI (p=0,001). Os não-brancos apresentaram chance de 5,4 vezes maior de terem Acantose Nigricans, os adolescentes, de 2,47 e os com Resistência Insulínica, de 2,66. CONCLUSÃO: Os resultados na população em estudo indicam a necessidade de treinamento voltado à identificação da Acantose Nigricans para profissionais de s...