Background: Neonatal brachial plexus palsy (NBPP) is a prevalent type of newborn morbidity with a potentially devastating persistence. Neurosurgical management is indicated in NBPP patients. The selection of those infants for surgery would be made easier by early prognostic assessment. Aim: To compare electrodiagnostics and imaging in the same patients because they have not previously been compared for precision in identifying infant brachial plexus avulsions. Patients and methods: This study looked back at 40 infants who had surgical NBPP and were treated between 2020 and 2022 in Faculty of Medicine, Zagazig University Hospitals in Plastic Surgery, Radiology, Neuro and Rheumatology Departments. To assess the performance accuracy of ancillary tests, in comparison to surgical findings, we reported electrodiagnostic testing (EDX) and imaging sensitivity, specificity and accuracy. Results: The mean age at surgery was 9.93±7.42 months. 45% were Narakas grade I–II, and 55% were Narakas grade III–IV. For all nerve roots, the overall accuracy of detecting avulsion was 55% for imaging and 65% for EDX. The overall accuracy of detecting rupture was 45% for imaging and 65% for EDX. Conclusion: Imaging and EDX are not as precise as was previously asserted. Given that each test's strengths frequently compensate for its weaknesses of the others, the ideal workup for patients with NBPP is likely to include a variety of modalities.