The Basic Trilingual Program at Flushing High School in New York City is described in this report. As implemented in 1980-1981, the program aimed to help 250 Spanish- and Korean-speaking high school students (grades 9 through twelve) to make the transition to English by adopting a comprehensive instructional approach consisting of intensive instruction in English as a second language; native language instruction and bilingual instruction in content areas for the Spanish speaking; and E.S.L. (English as a Second Language) approaches in content areas for Korean-speaking students. The report describes the program setting, objectives, organization, and participants; implementation of instructional and non-instructional program components; and program evaluation. Evaluation results indicate that: (1) both Hispanic and Korean students achieved gains in mastery of English syntax objectives; (2) among Spanish-speaking students, passing rates in mathematics, science, and social studies were generally higher for those taught in bilingual versus those taught in mainstream classes; (3) Koreans tended to have higher passing rates than Spanish speakers; and (4) program attendance was generally better than school-wide attendance. The report also presents the results of a survey of students' attitudes concerning the kind of assistance they would like from the program; problems; factors influential in getting good grades; and participation in various school activities. Recommendations for program improvement are presented. (Author/MJL)