Eleven of the cardinals were from outside Europe, including impoverished countries such as Burkina Faso and Haiti, the Italian news service ANSA reported.
The ceremony was also the first at which a former pope -- Benedict XVI -- was present. Benedict, who resigned last March, was greeted by Francis, who walked down the nave at St. Peter's Basilica to embrace him.
Monsignor Loris Capovilla was due to be the 19th cardinal named, but the 98-year-old former secretary to John XXIII was unable to attend because of frail health. He will be presented his biretta, a red cap signifying a cardinal's willingness to die for his faith, at a later date, CNN reported.
The cardinals are from 12 countries, with five from Latin America and the Caribbean, the BBC reported.
Francis told the cardinals the church needs "your compassion especially in this moment of pain and suffering in so many countries in the world."
Sixteen of the cardinals are under 80, allowing them to vote on a new pope when the time comes.
Becoming a cardinal should not been seen as a promotion, Francis told the clerics in a letter last month, CNN reported.
"It is simply a service that demands a broader vision and a bigger heart," he said.