From 1969 to 1988, 211 cases of spina bifida were collected from the Neurosurgical Clinic at the University Teaching Hospital of Dakar. Cases were reviewed for genetic and environmental factors. There were 103 males (48.81%) and 108 females (51.19%). The most important ethnic group involved were toucouleurs (20.11%). Consanguineous marriages in parents of affected infants were lower than in the general population (62.5% vs 71%). Recurrence has been noted in 4.26% of the cases. There were more fifth-born children affected than expected (16.2% vs 9% p < 0.02). A seasonal and geographic variation of the incidence has also been observed. Infants conceived between November and February appear to be of highest risk (36.16%). The incidence is higher in the north-west and lower in the south-east part of the country. Lower social-economic classes were the most involved. The authors support the hypothesis of multifactorial etiology in Spina Bifida.