Objective: Down syndrome is a common genetic disease, diagnosed with congenital malformation/mental retardation. Down syndrome occurs in all races & economic levels. It is caused by third copy of chromosome 21, there are there forms of DS. Simple Trisomy 21, Translocation Trisomy and Mosaic Trisomy. The aim of the study is to know cause of Down syndrome. Chromosomal analysis was carried out by G banding technique. Materials and Methods: 1 ml of peripheral blood samples were collected in Out Patient Department of pediatrics and Cytogenetic analysis was performed. Results: out of 28, 3 female cases, 2 male cases were Down syndrome, All the 5 cases were free trisomy 21, which is common type of Down syndrome; we have not identified Robertsonian translocation and mosaic type of DS. Conclusion: The present analysis shows that genetic risk factors are responsible for the incidence of Down syndrome
