The Holy See Press Office said that the discussions were "cordial" and said the two leaders spoke about the Pope's visit to the country last year.
The pair also spoke about the country's history and how the process of peace and reconciliation was progressing.
Pope Francis also heard about the role of the Catholic Church in society and the place of interfaith dialogue in Sri Lanka.
According to Vatican Radio the men talked about the environment and the promises that came from the COP21 Paris climate deal.
The men exchanged gifts and President Sirisena gave the Pope a silver vase. The Holy Father gave the Sri Lankan leader a wooden depiction of the Tree of Peace, made with two intertwined olive branches.