The incidence and causal factors of dropping out of school and grade repetition at the primary school level in the Nandi District of Kenya were examined. The study involved longitudinal analysis of primary school flow from 1976 to 1982 in five representative schools. Data were gathered through questionnaires and interviews with District Education Officers, headmasters, parents and chiefs of the areas studied, school staff members, and pupils. Social and economic backgrounds of the families of dropouts and parents' attitudes toward schooling were extensively explored. Analysis of findings indicated that parental ignorance and disinterest in education, pregnancies, and the low economic status of the family ranked high among the factors responsible for students' dropping out. Other factors included lack of school uniform, early marriages, cost of school fees, migration, lack of discipline, and illness. It is recommended that sex education should be emphasized to prevent girls from dropping out because of early marriage or unwed pregnancy and that parents and the public need to reorient their values and outmoded cultural attitudes. (JD)