Statement of problem: Research For adolescents indicates that the patient's sex did influence anticipatory , and girls had higher pain intensity scores . Whether differences extent to children is less clear, and further studies in this area are needed .The aim of this study was to determined the effect of gender on the pain intensity. Materials and Methods: In this RCT , 50 children 2-6month of age were taken (25 girls and 25 boys).In girls group and boys group DPT Vaccine via IM injection are Performed .Data was collected using FLACC scale and were analyzed with wilcoxon signed rank test . Results: Result showed that not significantly difference between severity of Pain due to DPT Vaccine IM injection in girls group as compared with boys group (P>0/5). Conclusion: Finding of this study indicated that gender could not Play an Important role in severity of pain 2-6 age of month children.