Evidence was collected regarding changes over 3 years in the quality of a preprimary program in rural Bangladesh and differences in school achievement of children who did and did not attend. The quality of 30 preprimary schools was evaluated using the ECERS-R (Early Childhood Environment Rating Scale-Revised) and ECERS-E (-Extension). Results indicated that the quality improved overall from 3.50 in 2006 to 5.24 in 2008. Samples of 180 graduates of these schools were annually followed into first and second grades and tested for five competencies: speaking, writing, reading, oral mathematics and written mathematics. Their achievement scores were compared with students in their classrooms and students in neighboring schools who did not have the opportunity to attend preprimary schools. First graders in 2008 performed significantly better than comparisons in all competencies, and better than earlier graduates. Second graders performed significantly better than comparisons on all but Reading. Qualities of the math preprimary program correlated with math achievement in Grade 1 only. Consequently the quality of the preprimary program improved over time along with higher achievement for its graduates. The findings support efforts to expand high-quality programs in developing countries to help children succeed in the early primary grades.