Each of the States was paired with a comparison State in which the legal minimum drinking age remained unchanged during the study period. Comparison States were chosen on the basis of geographic proximity to law-change States and comparability with law-change States regarding numbers of crash fatalities. Data on driver involvement in fatal crashes from January 1975 through September 1980 were obtained from the Fatal Accident Reporting System. The duration of postlaw periods studied ranged from 9 months to 3 years. Fatal crash involvement of drivers younger than those covered by the laws (starting with age 15) was also studied because of the possibility of spillover effects in these ages when alcoholic beverages could no longer be obtained legally by older teenagers. As a control, drivers older than those to whom the law changes applied (through age 21), who could drink legally in law-change States throughout the study period, were also included. The study indicates that when States raise the drinking age, there is a corresponding decrease in fatal crashes among law-affected drivers. 4 tables, 3 figures, and 8 footnotes.