Global developmental delay is the common pediatric problem having spectrum of underlying causes. Etiological diagnosis is very vital for providing information regarding pathogenesis, prognosis, recurrence, risk and treatment options. The aim of this study was to determine etiological yield of global developmental delay.This descriptive cross-sectional study included children of 6 months to 5 year of age with global developmental delay referred to pediatric outpatient Neurology clinic of Kanti Children's Hospital. Diagnostic study included detailed history, examination followed by required investigations neuroimaging, electroencephalogram, hearing and visual assessment. Thyroid function test, karyotyping and enzyme essay were done in selected patients depending on the condition.In this study, 110 patients were evaluated out of which 70 were male and 40 were female. An etiological diagnosis was determined in 86 (78%) of the patients classified under following categories perinatal asphyxia 49 (44.5%), post infectious sequelae 11 (10%), cerebral dysgenesis 6 (5.45%), genetic syndrome 6 (5.45%), metabolic causes 5 (4.54%), neurocutaneous syndrome 4 (3.63%) and non-specific leucodystrophy changes . Etiology was unknown in 24 (21 %) of the patients.A specific etiology can be determined in majority of cases of global developmental delay after comprehensive evaluation. The most common etiologies were perinatal asphyxia and post infectious sequelae.