Bilingual immersion programs combine second language immersion for language majority children and bilingual education for language minority children. The programs are based on the underlying assumption of the immersion model: that a second language is best learned as a medium of instruction, not as the object of instruction. However, they are not sheltered as are most immersion programs, and they serve the needs of both student language groups. This kind of program draws on the natural resources existing when two language groups are mixed in the same instructional setting: the children learn each others' languages. The San Diego Title VII Spanish-English bilingual immersion program is an example that has shown consistently high student achievement for oral language development, reading, and mathematics in both languages by the completion of elementary school. Implementation of a bilingual immersion program is complex, and requires careful consideration of such issues as feasibility, target groups, parent support, teacher pre-service and in-service training, curriculum and materials adaptation, administrator and staff roles, and maintenance of language group balance. (MSE)