Background and objectives: diaphyseal fractures in the pediatric age group should be perfectly treated. Treatment options are too many with long lists of pros and cons. This study aims to determine complications of elastic stable intramedullary as an evolving method in the era of operative treatment. Methods: This is a prospective case series study, conducted at Duhok Emergency Teaching Hospital between march/2021 and April/2022. The sample size was 100 children (mean age was 6.53 years). Inclusion criteria were: diaphyseal fractures (open and closed) in children 3-12 years. Exclusion criteria were: humeral fractures, fractures of the radial neck, pathological fractures, and obese patients (>40kgs). All of them were operated on under general anesthesia and their fractures were fixed with elastic stable intramedullary nails under C-arm, follow up period was 6-9 months both clinically and radiologically. Results: complications were found in the following order of frequency: 39.02% insertion site irritation, 14.02 joint swelling, 9.76% superficial infection, 7.93% loss of reduction, 7.32% stiffness, 3,66% delayed union, 3.05% limb length discrepancy and 0.61% deep infection. While the frequency of complications was significantly related to the type of fracture as (p-value: 0.031) and transverse fractures were seen to be associated with the highest complication rate, no significant relation was found between the frequency of complication with either age groups or gender as the (p-value: 0.447) for frequency of complications among both age groups and (0.711) between the two genders. Conclusion: fixation with elastic stable intramedullary nails is a good choice of treatment for diaphyseal fractures in the pediatric age group however it is not free of complications.