The fourth year of the partial immersion program in grades one through four at Key Elementary School (Arlington, VA), where half the day is taught in English and half in Spanish, is reported. Eight teachers and 85 students are involved in the 4 classes. As in other years, the "special" classes (music, physical education, and library) are conducted in English, but there is an increased awareness of Spanish language activities throughout the school. The annual review has included classroom observations, student and teacher interviews, student assessment, and parent and staff interviews. Student assessments measured progress in both Spanish and English (standardized tests, oral language assessments, and teacher evaluations). Reasons for the program's continued success are identified, including: teacher/staff dedication; coordination between the two immersion classes and between the English and Spanish parts of the day, including the approaches to reading, writing, and hands-on science instruction; active involvement of parents; and continued support for the program from the central office. A major recommendation is that the program be continued and expanded to involve grades 1-5. Additional recommendations call for teacher inservice training opportunities and for the implementation of a long-term plan for the continuation of Spanish instruction for immersion students in middle and high school. Appended are agendas from parent-teacher meetings, a newspaper article about the program, the school immersion brochure, and the Holistic Rating Scale for Writing Samples. (LB)