Introduction: Developmental delay is a term for children below 5 years who have delay in attaining milestones in two or more domains. Causes include infection, prematurity , metabolic causes, hypoxic ischemia, trauma and 20% of cases include genetic syndromes. Genetic syndromes include Fragile X, Prader-Willi, Angelman, Rett syndrome. These syndromes can be diagnosed by genetic testing which identify changes in genes, chromosomes or proteins. Case: A 9-month-old female child born to non-consanguineously married couple with history of two abortions presented with history of developmental delay with congenital hypothyroidism since 1 month of age & seizures from 4 months of age. Child attained partial head control, bidextrous reach and was able to recognize her mother. On examination, Dysmorphic features in the form of hypertelorism, low set ears with preauricular sinus, depressed nasal bridge, macroglossia with high arched palate and short neck. Spine examination revealed scoliosis. Nervous system examination showed generalized hypotonia with diminished deep tendon reflexes. Chest X-ray done showed 13 ribs on the right side with 11 ribs on the left side. As the clinical examination showed Dysmorphic features suggestive of genetic disease, genomic DNA for exome sequencing and deletion analysis was done, which revealed 3p26.3 – p25.3 Heterozygous deletion confirming the diagnosis of 3p deletion syndrome. Conclusion: 3p deletion syndrome is a rare disorder characterized by intellectual disability ,motor developmental delay , dysmorphic features such as microcephaly , micrognathia, ptosis, long philtrum, low set ears, polydactyly and hypotonia. Other rarer symptoms include congenital heart disease, renal, gastrointestinal malformations, autism, congenital hypothyroidism, seizures.