Several studies have identified the score on the math SAT as the best predictor of subsequent performance in freshman chemistry courses2-4, but what predicts success in organic chemistry, and how well does freshman chemistry predict grades in other science courses and success in entering medical school? We have tried to answer these questions by following a group of students through their four years at Columbia University and correlating various measures of their performance. MethodGrades and SAT data were obtained for all 254 freshmen enrolling in freshman chemistry at Columbia College, the all-male undergraduate division of Columbia University, in the fall of 1978, The overwhelming majority of these students are premed since engineers enroll in the School of Engineering from the beginning and only a tiny minority goes on in pure science. Few freshmen take biology or physics concurrently with freshman chemistry because of Columbia's other requirements.The raw grade data were converted to a numerical scale (A+ = 13, A = 12,... F = 0) and in all cases were "corrected" by subtracting the course mean. Thus a student who obtained a grade of B in a course with a mean of 8.19 would have a corrected grade of 9 -8.19 = +0.81. This corrects for differences in course means between years and between departments.