The purpose of this study was to investigate the effects of an abacus-based mental math program on the computation skills of an elementary student with visual impairment. This study was conducted following the multiple-probe design across skills. The participant was a third-grade blind boy, age nine, enrolled at D school for the blind. During the intervention phase, the researcher implemented an abacus-based mental math program for about 35 minutes per session (abacus practice for 20 minutes, mental math instruction and practice for 15 minutes) in a sequence of addition, subtraction, and multiplication. In each session, the student was asked to mentally compute 10 problems per session for addition, subtraction, and multiplication, respectively, given on a test in braille; the rate of correction and the speed in seconds for computation were measured to examine the effects of the program. The results indicated that his correction rates for addition, subtraction, and multiplication increased from 20%, 28%, and 30%, respectively, at baseline phase, to 70%, 95%, and 72% at the intervention phase. In comparison with the effect of the program on the accuracy of the student\'s mental math skills, the program did not indicate the distinct effect on the student\'s speed for mental computation.