Objective To explore the influence of melatonin receptor agonist Neu-P11 on the expression of IRS-1 and GLUT-4 in insulin-resistant 3T3-L1 adipocytes. Methods Insulin resistant 3T3-L1 adipocytes were induced with high glucose/high insulin for 24 hours, and then they were divided into 4 treatment groups: melatonin, Neu-P11, melatonin+luzindole and Neu-P11+luzindole. And non-treated insulin-resistant 3T3-L1 adipocytes were taken as control. Glucose consumption was detected by enzymatic method. IRS-1 and GLUT-4 protein expressions were detected by Western blotting analysis. Results After the insulin-resistant adipocytes were treated with melatonin and Neu-P11, the glucose consumption and the expressions of IRS-1, GLUT-4 proteins were significantly increased compared with the non-treated control group (P<0.05). The expressions of IRS-1, GLUT-4 proteins in melatonin+luzindole(melatonin receptor antagonist) and Neu-P11+luzindole groups were significantly decreased compared with melatonin alone or Neu-P11 alone groups (P<0.05), and were similar to those in the non-treated control group. Conclusion Melatonin receptor agonist Neu-P11 can increase glucose consumption, insulin sensitivity in insulin resistant-adipocytes, which might be associated with the up-regulation of IRS-1 and GLUT-4 protein expression.