This book, “A Study of causative factors found in children with developmental delay”, which is the collection of risk factors of developmentally delayed children. This research was done during 2008-2009 at Sweekaar Rehabilitation Institute for Handicapped, Secunderabad while the author pursuing her M. Phil in Rehabilitation Psychology. Book contains 5 chapters with references and appendix. It discussed the causative factors of pre peri and postnatal period of the children with the diagnosed cases of developmental delay. The developmental delay is caused by various factors and relate to motor, speech, sensory, and cognitive areas etc. The main finding of the study is to identify the causative factors in pre-peri and postnatal periods, which could go a long way in preventing mental retardation. After knowing some major causes, it is also important to know how to identify the problem as early as possible and reducing the incidence of developmental delay & subsequent associated disabilities through early identification and appropriate intervention. As the author have a mentally challenged sister, which motivated her to do the course of M.Phil in Rehabilitation Psychology.