Acanthosis nigricans (AN) is most commonly related to obesity as a manifestation of cutaneous insulin resistance in children and adolescents, while the interaction and time course between AN and obesity and detailed mechanism for the pre- and co-obese appearance of AN (PCOAN) in child are unclear. In this study, the involvement of insulin receptor in child PCOAN was investigated via studying the association of polymorphisms of INSR gene with PCOAN. In total, 99 children with PCOAN and 100 healthy controls recruited were genotyped and analyzed by PCR-RFLP method. Significantly different distributions were found in the frequency of the INSR His1085His genotypes, but not in other INSR genotypes, between the two groups. Our results provide not only the evidence that the T allele of INSR His1085His is correlated with the appearance of PCOAN but revealed that the insulin receptor pathway may play an important role in this PCOAN.