To test the hypothesis that participation in the School Breakfast Program by low-income children is associated with improvements in standardized achievement test scores and in rates of absence and tardiness, children in grades 3 through 6 were studied in the Lawrence, Mass, public schools, where the School Breakfast Program was begun at the start of the second semester 1986-1987 school year. The changes in scores on a standardized achievement test and in rates of absence and tardiness before and after the implementation of the School Breakfast Program for children participating in the program were compared with those of children who also qualified but did not participate. Controlling for other factors, participation in the School Breakfast Program contributed positively to the 1987 Comprehensive Tests of Basic Skills battery total scale score and negatively to 1987 tardiness and absence rates. These findings suggest that participation in the School Breakfast Program is associated with significant improvements in academic functioning among low-income elementary school children.