This evaluation research compares the first-grade competencies of two cohorts of Bangladesh children who attended "Succeed" preschools, with a control group who did not attend preschool. Testing of these groups occurred in 2006, 2007, and 2005, respectively. The Succeed program aims to improve children's learning and children's school success by developing and testing an affordable, sustainable preschool model that can be implemented in school, community and home settings. Researchers assessed the quality of school- and home-based preschool environments using the Early Childhood Environment Rating Scale (ECERS) plus two curricular subscales that tap program quality. An independently developed test based on government-defined competencies assessed school achievement of Grade 1 children. Results showed that children who attended Succeed preschools performed better in four of the five competencies relating to reading, writing, and oral math, compared with children without any preschool experience. Better quality preschool environments were positively associated with children's competencies in Grade 1. There were no statistically significant differences in first-grade performance between children from home-based preschools compared with school-based preschools, both using the same Succeed program. (Contains 3 figures and 3 tables.)