In 1961 the Right Reverend A.J. Verineux, Bishop of Yingkow, Administer Apostolic of Hwalien wrote to Mother Mary requesting Sisters to work in the Apostolic prefecture of Hwalien (Formosa, as it was then).

The founding members Sr. Kieran Saunders and Sr. Maria Glancy left Drogheda on 23 November 1961 and travelled via Rome, Bangkok, Hong Kong and reached Taiwan on 15 December 1961. Sr. Petria Whelan followed.

The Holy Cross Congregation of Sisters handed over the medical work to MMM and the building of the convent and hospital continued with the MMM Sisters moving into their new convent 11 November 1963.

Some girls showed interest in joining MMM and subsequently did so in 1964 as aspirants/postulants but the Sisters then faced the difficulties of these girls having a poor standard of English and the enormous challenge of getting exit visas for them to leave the country to go to Ireland for further formation.  In 1967 the remaining one of these aspirants who had been living in community with the Sisters left and subsequently married.

In 1974, at the Third Congregational Chapter a decision was made to close the mission in Taiwan.  One of the Sisters living in Taiwan at the time, Sr. Maureen Sinnott, was part of the decision making process.  Some of the reasons given were:- the isolation from the rest of the Congregation, the fact that there were many other hospitals in Taiwan, there was no possibility of entering mainland China for expansion, visa difficulties and a lack of vocations to the MMM way of life.