The first mention of Tullaghan church is in Griffiths Valuation, published in 1858, which notes that it was in the townland of Tawnytallen and it was a Roman Catholic Chapel and yard, 20 perches in area. The census of Ireland 1851, published by Alexander Thom in 1852 has a note that the valuation of the County of Leitrim under the direction of Mr. Griffith was made in 1842. This would indicate that the church was on its present site in 1842.

Originally the church was T-shaped with the sanctuary beside the road. Major reconstruction was begun in 1937. James Donnelly of Enniskillen was architect and John Donnelly & Sons (his brother) were the contractors. The sanctuary was placed at the northern end of the church, the nave was lengthened and a new sacristy was erected.
The re-dedication was carried out by Dr. Patrick Lyons on 16th April 1939.

The bell tower was erected and blessed by Dr. Quinn in that year. The sanctuary was modified in 1971, the church was rewired in 1975 and further repairs were carried out in 1980. At the present time plans are in place to have the exterior of the church repainted.