The St. Mary's Cathedral was built in 1808 by Paschal Mudaliyar. The church became a cathedral after Batticaloa Diocese was formed in the year 2012.
It was in the year 1893 the Trincomalee diocese was acknowledged and then in 1965 the Trinco-Batticaloa diocese was formed comprising churches of the eastern province districts. At this juncture the St. Mary’s Church was named as Co-Cathedral; and became the first Co- Cathedral in Sri Lanka’s church history.
On 3rd July 2012, in keeping with the decision of the Holy Father Benedict, His Archetypal in Sri Lanka, Rev.Dr Joseph Spitteri, declared Batticaloa as a new diocese and ordained Rt. Rev. Dr. Joseph Ponniah as the Bishop of Batticaloa. With this appointment the Co-Cathedral was raised to the rank of Cathedral. Its been a historically important church among the Catholics living in Batticaloa. Christianity was introduced in Batticaloa and Trincomalee by the Portuguese in the 16th century