THIS PRELIMINARY STUDY FOCUSES ON JUVENILES 18 YEARS OF AGE AND YOUNGER WHO BECOME INVOLVED WITH THE COURTS AND MEET THE MENTAL RETARDATION DEFINITIONS OF THE AMERICAN ASSOCIATION ON MENTAL DEFICIENCY (AAMD) AND NEW JERSEY'S DIVISION OF MENTAL RETARDATION (DMR), DIVISION OF YOUTH AND FAMILY SERVICES (DYFS), DEPARTMENT OF CORRECTIONS, AND JUVENILE JUSTICE SYSTEM. REMARKS RECOUNT JUVENILE JUSTICE PROFESSIONALS' PERCEPTIONS OF EACH STEP OF THE JUVENILE JUSTICE SYSTEM AS IT AFFECTS A MENTALLY RETARDED CHILD. PROCEDURES FOLLOWED BY NEW JERSEY'S DYFS ARE DETAILED, WITH ATTENTION TO DYFS' RELATIONSHIP WITH DMR, TO DYFS REFERRAL SERVICES, AND TO DYFS' GENERAL IGNORANCE ABOUT MENTAL RETARDATION. POPULATION SIZE, LEVELS OF RETARDATION, SEX, AGE, FAMILY STRUCTURE AND INCOME, AND TYPE OF OFFENSE ARE REPORTED AS IDENTIFIED THROUGH DMR RECORDS OF PERSONS REFERRED TO THEM. FURTHER RECORDS OUTLINE INFORMATION REGARDING COUNTY AND ORIGIN OF REFERRAL, BEHAVIOR MANAGEMENT PROBLEMS, AND LENGTH OF CONFINEMENT FOR ADOLESCENTS ACCEPTED BY DMR FACILITIES. CORRECTIONS INFORMATION MENTIONED RELATES TO THE SIZE AND CHARACTERISTICS OF THE TARGET POPULATION IN FACILITIES OPERATED BY THE DEPARTMENT OF CORRECTIONS: THE SKILLMAN TRAINING SCHOOL FOR BOYS, THE JAMESBURG TRAINING SCHOOL FOR GIRLS AND BOYS, AND THE YOUTH CORRECTIONAL INSTITUTIONS COMPLEX. CHARTS, GRAPHS, TABLES, A BIBLIOGRAPHY, AND A JUVENILE JUSTICE SYSTEM FLOW CHART PROVIDE ADDITIONAL DATA. RECOMMENDATIONS ARE BRIEFLY DEVELOPED FOR A TASK FORCE TO PURSUE STATUTE AND REGULATIONS REVIEWS, AND TO FURTHER PERSONNEL TRAINING AND THE DEVELOPMENT OF DISPOSITIONAL ALTERNATIVES. (MHP)