A secular institute is an institute of consecrated life in which the Christian faithful living in the world strive for the perfection of charity and work for the sanctification of the world especially from within.
Secular institutes first received papal recognition from Pope Pius XII in Provida Mater Ecclesia (1947). Secular institutes are recognized either by a bishop (diocesan right) or by the Holy See. Most are registered in the World Conference of Secular Institutes. There are nine secular institutes in the UK. These institutes belong to the National Conference of Secular Institutes (NCSI). This is an association for co-operation and mutual support of those secular institutes which have membership in the United Kingdom. The NCSI is affiliated to the Conference Mondiale des Instituts Seculiers (CMIS) which represents all secular institutes in the world.
Currently, up to 60,000 members belong to more than 200 secular institutes in the world. Most of the members of secular institutes are lay people. Some join as diocesan priests or deacons, and some institutes are founded specifically for diocesan priests who wish to take vows and lead a consecrated life while still being incardinated in their diocese and working in the diocesan framework. Some secular institutes even train and incardinate their own priests.