The effectiveness of the Law School Admission Test (LSAT) as a predictor of first-year law school grades was evaluated in a series of studies initiated in the summer of 1949. This report is based on the findings of studies in eighteen law schools, including twelve schools which provided data on some measure of the previous academic success of their students. The eighteen law schools on which this report is based include all schools now represented on the Policy Committee of the Law School Admission Test which had test scores on 25 or more students. The principal finding of this study is that Law School Admission Test scores are distinctly useful alone or preferably as supplementary to evidence of previous academic success in predicting first-year grades of law students. This conclusion is based on the fact that the predictive effectiveness of the combined predictors is represented by a correlation coefficient of .52, as compared with a value of .40 for the test alone and of .38 for previous academic success alone. These figures summarize results based on 1,725 day students in 12 law schools. In ten of these twelve schools the test score equalled or excelled the college record as a predictor of first-year law grades.