Johann Baptist Malfatti, Edler von Monteregio baptized as Giovanni Domenico Antonio Malfatti (June 12, 1775, in Lucca – September 12, 1859, in Hietzing near Vienna) was an Italian/Austrian doctor famous for treating the composer Ludwig van Beethoven.

In 1809 he published his work of natural philosophy, "Draft pathogeny of Evolution and Revolution of Life."

During the Congress of Vienna he enjoyed an excellent reputation and became the personal physician of Archduke Karl and Archduchess Maria Beatrice d'Este of Modena.

Ludwig van Beethoven first made Malfatti's acquaintance in 1809 and consulted him several times in the following years.

He engaged in personal contact with the philosophers Franz Xaver von Baader and Friedrich Wilhelm Joseph Schelling, the naturalist Lorenz Oken, and the medical philosopher Ignaz Paul Vital Troxler.