Background: According to the World Health Organization, about 5% of children world-wide of 14-year-old and under have a moderate to severe developmental disability, and up to 15% of children under 5-year-old are developmentally delayed. Purpose: To determine the prevalence, socio-demographic profile, aetiologies, and the clinical presentation of developmental delay in children less than 6-year-old at the child neurology unit in a university-affiliated hospital in Yaounde. Materials and methods: It was a crosssectional descriptive study carried out in Yaounde Gynaeco-Obstetric and Paediatric Hospital (Cameroon) from August to December 2012. Children aged between 5 - 72 months with a developmental quotient less than 70 were enrolled. Developmental delay (DD) was diagnosed and classified using the Denver developmental screening test (DDST). Data concerning the child (age, gender, severity of DD), the mother (age, age at conception, educational level, marital status), history of pregnancy and delivery, perinatal and postnatal events, results of para-clinical explorations (EEG, CT-scan, genetic tests), the severity of DD and the probable or demonstrate cause of DD were recorded on a standardized questionnaire. The chisquare test was used to compare variables. Results: During the study period, 2171 children aged 5 - 72 months consulted the paediatric department of the hospital, 296 were examined at the child neurology unit of which 153 had a developmental quotient less than 70, giving a hospital prevalence of 7.0% and a prevalence of 51.7% at the child neurology unit. The mean age was 26.6 ¡À 18.0 months and there were 56% males. The main reason for consulting was tonus disorder (43.8%) and the developmental area of parental concern was the motor domain (90.2%). Regarding the clinical presentation, 75.2% of our population were children with cerebral palsy. DD was severe, mild, moderate and profound respectively in 14.2%, 13.5%, 12.2%, and 11.1%. Gross DD represented 90.2% of all DD children. The causes of DD were hypoxic-ischemic encephalopathy (41.8%), epilepsy (13.7%), sequelae of meningitis (6.5%), sequelae of kernicterus (6.5%), and infectious embryofoetopathies (5.2%). Conclusion: Developmental delay is frequent in paediatric neurology, with perinatal disorders being the leading aetiologies in Cameroon. Prevention of perinatal hypoxic-ischemic encephalopathy risk factors %K Developmental Delay %K Risk Factors %K Aetiologies %K Hypoxic-Ischemic Encephalopathy %K Children %K Cameroon %U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=36616