In this Mexican potato study, Vitazyme applied at 1 liter/ha at planting and again two weeks later produced an excellent, significant (at P=0.05), 16% yield increase. This increase translated into 10,300 pesos/ha more net income, while increasing the percentage of first class tubers from 26% in the control to 34% with Vitazyme. Four Vitazyme applications did not increase yield but improved the tuber quality even further, by producing 36% first class tubers. Vitazyme at two applications per cropping cycle is an excellent potato treatment in Mexico.