Vincent de Paul had established the Daughters of Charity almost at the same time as the exercises des ordinands. At first they were intended to assist the conferences of charity. When these conferences were established at Paris (1629) the ladies who joined them readily brought their alms and were willing to visit the poor, but it often happened that they did not know how to give them care which their conditions demanded and they sent their servants to do what was needful in their stead. Vincent conceived the idea of enlisting good young women for this service of the poor. They were first distributed singly in the various parishes where the conferences were established and they visited the poor with these ladies of the conferences or when necessary cared for them during their absence. In recruiting, forming, and directing these servants of the poor, Vincent found able assistance in Mlle Legras. When their number increased he grouped then into a community under her direction, coming himself every week to hold a conference suitable to their condition. (For further details see Sisters of Charity.) Besides the Daughters of Charity Vincent de Paul secured for the poor the services of the Ladies of Charity, at the request of the Archbishop of Paris. He grouped (1634) under this name some pious women who were determined to nurse the sick poor entering the Hotel-Dieu to the number of 20,000 or 25,000 annually; they also visited the prisons. Among them were as many as 200 ladies of the highest rank.

After having drawn up their rule St. Vincent upheld and stimulated their charitable zeal. It was due to them that he was able to collect the enormous sums which he distributed in aid of all the unfortunates. Among the works, which their co-operation enabled him to undertake, that of the care of foundlings was one of the most important. Some of the foundlings at this period were deliberately deformed by miscreants anxious to exploit public pity. Others were received into a municipal asylum called "la couche", but often they were ill-treated or allowed to die of hunger. The Ladies of Charity began by purchasing twelve children drawn by lot. who were installed in a special house confided to the Daughters of Charity and four nurses. Thus years later the number of children reached 4000; their support cost 30,000 livres; soon with the increase in the number of children this reached 40,000 livres. With the assistance of a generous unknown who placed at his disposal the sum of 10,000 livres, Vincent founded the Hospice of the Name of Jesus, where forty old people of both sexes found a shelter and work suited to their condition. This is the present hospital of the uncurables. The same beneficence was extended to all the poor of Paris but the creation of the general hospital which was first thought of by several Ladies of Charity, such as the Duchesse d'Aiguillon. Vincent adopted the idea and did more than anyone for the realization of what has been called one of the greatest works of charity of the seventeenth century, the shelteringof 40,000 poor in an asylum where they would be given a useful work. Inanswer St. Vincent's appeal the gifts poured in. The king granted the lands of the Salpétriere for the erection of the hospital, with a capital of 50,000 liveres and an endowment of 3000; Cardinal Mazarin sent 100,000 livres as first gift, Président de Lamoignon 20,000 crowns, a lady of the Bullion family 60,000 livres. St. Vincent attached the Daughters of Charity to the work and supported it with all his strength.