The effects of early education bilingual programs on subsequent educational achievement were studied with Spanish-speaking children of migrant farm workers in southern Texas. The children were enrolled in the Individualized Bilingual Instruction (IBI) program for at least one year from preschool through grade 3. About 30-50 children were tested at each grade level, and a like number were tested in a neighboring school for a comparison group. IBI children and the comparison group of Spanish-speaking, migrant farm worker children did not differ significantly on pretests. For the followup study, about 10 IBI children and about 15 comparison group children were tested at each grade level, grades 4-6. At this time, IBI children had been out of the IBI program from 1-5 years. IBI children had special instruction one hour a day. During the winter months, they were taught in the home base area, while special instruction was continued in temporary locations in the north during the migrant work season. The instructional materials were structured and sequenced, and the lessons were individualized. Frequent mastery checks were also provided. For the followup study, the Peabody Picture Vocabulary Test and the math and reading subtests of the Wide Range Achievement Test were administered to students. FIndings include: (1) IBI children learned English much faster than children in the comparison group; (2) IBI children maintained and improved their Spanish; (3) IBI children achieved much higher scores in reading and arithmetic than comparison children; and (4) the IBI children's superiority was maintained at upper grade levels after they left the program. (SW)