PREKINDERGARTENS IN 8 NEW YORK STATE SCHOOL SYSTEMS WERE EVALUATED TO FIND OUT IF THE CHILDREN INVOLVED SHOWED INCREASED CAPACITY TO LEARN, AND IMPROVEMENT IN LANGUAGE AND COGNITIVE SKILLS. 1010 DISADVANTAGED AND 225 NONDISADVANTAGED SUBJECTS WERE RANDOMLY ASSIGNED TO EXPERIMENTAL AND CONTROL GROUPS AND PRE- AND POST-TESTED WITH THE STANFORD-BINET AND THE PEABODY PICTURE VOCABULARY TEST. AT THE END OF THE PREKINDERGARTEN YEARS THE ILLINOIS TEST OF PSYCHOLINGUISTIC ABILITIES WAS GIVEN, AND LATE IN THE KINDERGARTEN YEAR THE METROPOLITAN READINESS TESTS WERE USED TO SEE IF GAINS OBTAINED DURING PREKINDERGARTEN WERE SUSTAINED OR INCREASED. THE GENERAL CURRICULUM IN ALL PROGRAMS WAS THE SAME, BUT CERTAIN ACTIVITIES WERE ADDED TO SELECTED CLASSES. CHILDREN WHO WERE GIVEN READING READINESS INSTRUCTION OR LANGUAGE TRAINING SHOWED THE GREATEST GAINS. IMPLICATIONS ARE THAT THE MOST EFFECTIVE PREKINDERGARTEN PROGRAMS ARE THOSE WHOSE CONTENT IS DESIGNED TO DEVELOP COGNITIVE ACTIVITIES EFFECTIVE IN INCREASING LEARNING CAPACITIES. IT ALSO APPEARS THAT PREKINDERGARTEN EFFECTS WILL BE MOST LASTING IF SPECIAL PROGRAMMING FOR THE DISADVANTAGED IS CONTINUED INTO THE PRIMARY GRADES. THIS PAPER WAS PRESENTED AT THE 1967 ANNUAL CONVOCATION OF THE EDUCATIONAL RESEARCH ASSOCIATION OF NEW YORK STATE, NOVEMBER 14, 1967. (MS)