The partial immersion program at Key Elementary School (Arlington, Virginia), where half the day is taught in English and half in Spanish, continued to be successful in its ninth year. Reasons for success include: dedication and in-depth understanding of immersion philosophy among principal, coordinator, teachers, and staff; innovations in both English and Spanish portions of the day, especially in approaches to reading and writing; active parent involvement; supplemental federal funding; and continued central office support. Tests indicate participating students have progressed in academic areas as well as or better than other students at their grade level, both within the school and in comparison with state and national norms. Four years of federal funding have enabled the immersion program to improve, enrich, and expand its established program, including addition of a kindergarten program, curriculum development, development and revision of portfolio assessment procedures, in-service training for immersion teachers, English and Spanish language classes for parents, and staff development. Recommendations for the following year include: initiation of a yearly evaluation of the entire Arlington immersion program; establishment of a teacher mentoring program; kindergarten day expansion; continuation of the staff position of immersion program coordinator; and continued increase in student ethnic diversity. (MSE)