This work was designed to verify the effect of heterosis on the physiological quality of corn seeds. Seeds of six lines coming from the corn breeding program of the ?Universidade Federal de Lavras, UFLA?, and of their respective simple hybrids and reciprocal simple hybrids were produced in the experimental area of the UFLA. The evaluation of the physiological quality was performed in the Seed Analysis Laboratory of the UFLA, through germination, vigor and biochemical tests. The tests performed for the evaluation of physiological quality followed the completely randomized design with four replications and the comparasion of the means was done by Scott and Knott?s test. The obtained data in evaluating the physiological quality of seeds, lines and hybrids were utilized to estimate the values of heterosis. The results enabled to conclude that the hybrid corn seeds presented superior physiological quality as compared to those of the lines, stressing in this way the expression of heterosis on the physiological quality of seeds.