Proceedings from the International Summit on Prevention of Mental Retardation from Biomedical Causes are provided. After a list of participants and summary of the highlights of the conference, the keynote address by H. Moser is presented. The following 13 papers are provided along with workshop recommendations and a list of main points elicited from the discussions (which are included for most papers): "Preventing Mental Retardation--More Can Be Done" (J. Dion); "A National Program to Prevent Neural Tube Disorders" (A. Milunsky); "Regionalization and Expansion of a Metabloic Screening Program for New Borns" (R. Guthrie); "Prevention of Rh Hemolytic Disease" (R. MacCready); "Strategies for Prevention of Mental Retardation at the Federal Level" (E. Boggs); "Nutrition, Brain Growth, and Prevention of Mental Retardation" (P. Rosso); "Prenatal Supplements and Breast Feeding" (R. Acosta); "Regionalization of Perinatal Care" (L. Gluck); "A Model Program for Lead Screening" (S. Piomelli); "Immunizations and What Can Be Done to Improve Their Use" (J. Browder) with comments and concerns expressed by T. Tjossem; "Maternal Alcoholism and Fetal Abnormalities" (K. Jones); and "Down's Syndrome and Its Potential Prevention" (M. Giannini). A list of commitments made by participants is followed by a concluding statement by R. Koch. (PHR)