Bivariate, regression, and path analyses were used to examine the association between socioeconomic and demographic variables and cumulative fertility in Lesotho. Variables are all endogenous except for place of residence and current age of women, which are exogenous. Data were obtained on 2737 currently evermarried women 15-49 years from the 1977 Lesotho Fertility Survey. The research problem is defined, and a conceptual framework, based on Easterlin and Crimmins, outlined. Socioeconomic and cultural determinants affect fertility regulation cost, demand for children, and supply of children, which affect use of fertility control, and other proximate determinants, which affect fertility. The population characteristics of Lesotho are 89% rural and homogenous. 37% of males and 16% of females have never attended school. 36% of women and 60% of men >10 years have had at least 4 years of schooling. The bivariate analysis revealed that the most important variables in producing differentials in cumulative fertility, contraceptive use and knowledge, age at 1st marriage, duration of breast feeding, child survival, and desired and total children were education, childhood place of residence, and occupation. Other variables that did not significantly affect fertility, contraceptive use, or intervening variables were religion and region of residence. In the regression analysis, 72% of the variance in children ever born (CEB) is explained by socioeconomic and demographic variables, followed by additional number of children desired, current age, and age at marriage. Demographic variables have greater explanatory power than socioeconomic variables. Direct effects on CEB were achieved in the path analysis by current age of women, age at 1st marriage, additional children desired, proportion of children dead, and breast feeding. The indirect paths are very similar although some variables change directions. It is suggested that raising the level of education and promoting greater urbanization would lead to fertility reduction; infant mortality should also be reduced.