THE EFFECTS OF A CONTROLLED THERMAL ENVIRONMENT ON PUPIL LEARNING WERE ANALYZED. APPROXIMATELY 20 MATCHED PAIRS OF FIFTH-GRADE STUDENTS WERE SELECTED. TWO GROUPS WERE USED--ONE FOR AN IDEAL THERMAL ENVIRONMENT AND THE OTHER FOR A DEVIATE THERMAL ENVIRONMENT. THE STUDENTS WERE MATCHED BY INTELLIGENCE TEST SCORES, ACHIEVEMENT TEST RESULTS, SEX, AGE, AND FAMILY BACKGROUND. THE CLASSROOMS WERE IDENTICAL IN ALL PHYSICAL ASPECTS. TEACHING INSTRUCTION FOR BOTH GROUPS WAS IDENTICAL, AND A WEEKLY ACHIEVEMENT SCORE WAS COLLECTED FROM ALL PARTICIPATING STUDENTS. THE STUDY LASTED ALMOST NINE SCHOOL WEEKS. RESULTING DATA WAS STATISTICALLY ANALYZED USING VARIANCE PROCEDURES. THE CONCLUSION REACHED BY THIS STUDY WAS THAT STUDENT LEARNING IS NOT AFFECTED BY ATTENDING SCHOOL IN A CONTROLLED IDEAL THERMAL ENVIRONMENT. (JH)