The number of inmates in Athy Workhouse fell dramatically after the ending of the Great Famine. At the height of the Famine almost 1,400 men, women and children were housed in the Poor House. The fall in numbers was largely due to the introduction of a system of outdoor relief which allowed poor families to obtain Indian meal without becoming inmates of the local Workhouse. Another reason was the high level of emigration from the South Kildare area in the years following the Famine. In 1855 there were 516 inmates in the Workhouse and six years later the numbers had dropped to 296. Thereafter there were seasonal fluctuations in the inmate population of Athy Workhouse with the highest number usually registered in January and February of each year when employment was unavailable and the weather was at its worst. In February 1862 the inmates totalled 392, an increase of almost 100 since the previous December. Poverty in the town of Athy was a cause of concern. On the 10th of January, 1863 it was reported that the mortality rate in Athy from various causes had been unusually high - six persons having died on Old Christmas Day. The extensive use by the poor and the labouring classes of a cheap American bacon was considered to be the cause of these deaths. That same month the Board of Guardians, as part of its outdoor relief scheme, employed an extra thirty local men to dig the Workhouse lands for one shilling per day each.
In the first quarter of 1863 there were 107 cases of fever reported in Athy. The Fever Hospital had been built in 1836 at a cost of £300 with monies collected by the local townspeople for a Mr. Keating of Market Square whose shop premises had been destroyed by fire. A respected and obviously well-liked individual, Keating donated the money for the building of a Fever Hospital in Athy. Officially designated a District Fever Hospital under the Fever (Ireland) Act 1847, the Athy Hospital remained independent of the Board of Guardians until 1854. In that year it was put on the Union which meant that the Poor Law Union of Athy was in part, at least, responsible for its running costs. The Board of Guardians fulfilled their obligations in this regard by agreeing to pay the sum of one shilling per day for each Workhouse patient maintained in the Fever Hospital.
Early in 1846 the Board of Guardians were required to equip Hospitals and Dispensaries for the sick poor. A voluntary dispensary committee had been operating in Athy since 1818 and it now became a sub-committee of the Board of Guardians. A small Infirmary was provided within the Workhouse to meet the responsibility of the Board of Guardians with regard to medical services for the poor. It was to this Infirmary that the Sisters of Mercy came as nursing sisters in October 1873.
The Sisters of Mercy from the local Convent apparently began to visit patients in the Infirmary on Sundays and over time they built up a relationship and an understanding with the patients. This encouraged the Board of Guardians to approach the Sisters of Mercy to take over the running of the Infirmary. The nuns agreed to do so and by March 1880, they were looking after the needs of 89 patients in the Workhouse Infirmary. In November 1885 John McLoughlin, a member of the Board of Guardians, referred to the time
"when the Board was a hostile camp composed of rabid Tories with a strong mixture of brutal Whigs... we may feel justifiably proud of what has been done. Look to the Chapel, look to the officers of the House and compare them to the officers of twenty-five years ago when we had not a Catholic officer at all and see how we have sanctified the place with the holy women introduced into the House instead of drunken nurses as in olden days".
His comments met with the approval of his fellow Guardians.
In June 1886 the Workhouse advertised for a Midwife to be employed in the Infirmary at five shillings per case attended. While the Sisters of Mercy continued to work in the Infirmary during daylight hours, there were no qualified Nurses employed to look after the patients at night time. This was the era of pauper nursing when female inmates were locked into the Hospital Wards with the patients at night and were required, as best they could, to look after them. This situation did not change until August 1897 when the Board of Guardians agreed to appoint a trained Night Nurse at a time when there were up to 80 patients in the Infirmary.