"We are united in prayer for Father Machorro who just was gored in the neck in the cathedral," fellow priest Jose Aguilar said on Twitter.
Dozens of worshipers were on hand at the Mexico City cathedral, Latin America's largest and a popular tourist draw on the landmark Zocalo square, when the assailant stabbed the priest.
The priest was rushed to hospital for treatment of neck wounds, police said. They declined to give the identity of the assailant, who was turned over to prosecuting authorities.