He called it a "humanitarian catastrophe" that is "severely testing our brothers and sisters, among them many children."
Benedict issued his appeal after giving his weekly blessing to pilgrims at his summer residence in Castelgandolfo, in the Alban Hills south of Rome.
Aid agencies say the East African drought is one of the worst in years in terms of the number of people affected.
Thousands of Somali refugees are flooding camps in Ethiopia and Kenya in search of food after several seasons without rain decimated livestock and killed crops in their homeland.
Benedict said he was following the crisis "with great concern" and that he hopes the international community will mobilise quickly.
"I call on all good-hearted people to keep up our solidarity and consistent support to these suffering populations," the pope said.
