Poor educational attainment is a persistent problem among Latino children relative to non-Latinos. This study examined the effects of participation in the Head Start program on Latinos. Large and significant benefits were found to accrue to Head Start children when compared to siblings who did not participate in the program. On average, Head Start participation closes at least one-fourth of the gap in test scores between Latino children and non-Hispanic white children, and two-thirds of the gap in the probability of grade repetition. Latinos are not a homogeneous group, and it was found that the benefits of Head Start are not evenly distributed across sub-groups. Relative to siblings who attend no preschool, the gains from Head Start are greatest among children of Mexican origin and children of native-born mothers, especially those whose mothers have more human capital. In contrast, Latino children whose mothers are foreign-born and Puerto Rican children appear to reap little benefit from attending Head Start, relative to their siblings who do not attend. (Five tables contain data on: (1) family background characteristics and child outcome measures; (2) impact on test scores and grade repetition; (3) effects on child outcomes; (4) effects on test scores; and (5) probability of attending Head Start versus other preschools. Contains 60 references.) (Author/SD)