Since independence in 1963, Kenya has invested substantial resources in the education sector. For almost twenty-five years, these investments and other government policies led to impressive gains in educational access at all levels. However, since the mid- to late 1980s there appears to have been an erosion in educational participation and a reversal of the gains achieved in previous decades. Motivated by this trend, this paper uses temporal, cross-section and pseudo-panel data to assess the plausibility of various factors that may be responsible for the decline in primary school educational enrolment. In particular, we consider the role of school fees, school inputs and curriculum, school availability, the expected benefits of education and the spread of HIV/AIDS. We also try to identify the most effective policy interventions that may be used to prevent further declines in primary school enrolment rates. Copyright 2004, Oxford University Press.