TO SUPPORT THE PREMISE THAT EARLY EDUCATION REDUCES ENVIRONMENTAL DEPRIVATION AND TO SUBSTANTIATE PROPOSALS ADVANCED BY BEREITER AND ENGLEMANN IN "TEACHING DISADVANTAGED CHILDREN IN PRESCHOOL," AN EXPERIMENT WAS CONDUCTED IN A HEADSTART SETTING. TWO CLASSES, EACH OF 24 CHILDREN RANGING IN AGE FROM 3-8 TO 5-7, ATTENDED PRESCHOOL CLASSES FOR TWO AND ONE-HALF HOURS DAILY AT THE MCKINLEY SCHOOL IN YORK, PENNSYLVANIA. INSTRUCTIONAL CONTENT, TEACHING STRATEGIES, AND PRESCHOOL MANAGEMENT PROCEDURES FOLLOWED THE PROGRAM WHICH BEREITER AND ENGLEMANN OUTLINED IN THEIR BOOK. THE CHILDREN WERE ALSO INSTRUCTED IN LANGUAGE, READING, AND ARITHMETIC FOR AN HOUR EACH DAY FOR 6 MONTHS. THE STANFORD-BINET INTELLIGENCE TEST WAS GIVEN DURING A 2-WEEK POST-TEST PERIOD. A YEAR LATER TWO SUBTESTS OF THE ILLINOIS TEST OF PSYCHOLINGUISTIC ABILITIES, AUDITORY VOCAL AUTOMATIC AND AUDITORY VOCAL ASSOCIATION, WERE GIVEN TO 38 OF THE 48 CHILDREN WHO THEN HAD 8 MONTHS OF PRESCHOOL EXPERIENCE, 2 MONTHS OF SUMMER EXPERIENCE, AND 1 MONTH OF KINDERGARTEN EXPERIENCE. RESULTS INDICATED THAT LONG-TERM EXPOSURE TO THE BEREITER-ENGLEMANN PRESCHOOL CURRICULUM INCREASED INTELLIGENCE QUOTIENT LEVELS AND STIMULATED DEVELOPMENT IN REASONING ABILITY, LANGUAGE FACILITY, AND UNDERSTANDING. THIS PAPER WAS PRESENTED AT THE AMERICAN EDUCATIONAL RESEARCH ASSOCIATION CONFERENCE (NEW YORK, FEBRUARY 18, 1967). (NS)