This paper reports on a longitudinal study of the Project Preschool PLUS bilingual program conducted by two elementary schools in Jefferson Parish, Louisiana. The program serves limited English proficient (LEP) students, the majority of whom qualify for free or reduced price lunches. It emphasizes whole group, small group, and individualized instruction, as well as field trips. Standard diagnostic tests were administered to students at the beginning and end of the school year during the preschool program, while the California Achievement Test (CAT) was administered to kindergartners and first-graders who had completed the program. The study found that Project PLUS was able to make noteworthy impacts on the preschoolers who finished the program. Seventy-one percent of these students were developmentally at or above their chronological age by the end of the school year. On all subscales of the CAT, the former PLUS students scored significantly higher than a control group of similar LEP students. (MDM)