Kate M. Youngman (December 17, 1841 – September 29, 1910) was an American missionary who established the Ihaien leprosy hospital in Tokyo, Japan, in 1894.

In October 1894, Ihaien was started on 4,950 square meters of land at Meguro, Tokyo.

Kitasato Shibasaburō proposed to send doctors and supplies if Ihaien would change to a hospital which was accomplished in 1899.

The original idea of the Ihaien was to house people with leprosy and let them live with spiritual comfort.

[1] The Ihaien Hospital was closed in 1942 because of financial difficulties, and 55 patients were transferred to Tama Zenshoen Sanatorium.