Background: Insulin resistance (IR) is associated with a higher risk of multiple diseases and its early detection would allow to minimize the associated risk; the presence of acanthosis nigricans (AN) it´s associated to the presence of IR. Objective: To evaluate the sensibility and specificity of AN to diagnose IR in a group of Chilean patients. Methods: We designed a cross-sectional study and it was included subjects that were attended at the Center for the Attention of Metabolic Diseases at the Faculty of Medicine, University of Chile. Sixty subjects (18-60 years age) were included. It was determined BMI and diagnosed AN and skin phototype; blood samples were taken and calculated the HOMA-IR. The normality of the variables where analyzed by Kolmogorov-Smirnov test. There were used χ² and the diagnostic concordance between AN and IR was determined using the Kappa index and Pearson´s correlation. Sensibility, specificity, positive and negative predictive value were calculated and accepted p < 0.05. Results: The IR diagnose was 67% and AN was 43%. The major proportion of subjects diagnosed as positive for IR were also positive for AN (84.6%). The sensibility of AN to find IR was an 84% and specificity was 100%. Positive and negative predictive values were 100% and 89% respectively. It was observed a positive association between BMI and HOMA-IR (r = 0.674; r² = 0.454; p < 0.001). Conclusion: To detect acanthosis nigricans in Chilean population may be effective for the early diagnose of insulin resistance and, therefore, reduce the associated cost of the late treatment of glucose metabolic disturbances.