The German naturalist Juan Cristóbal Gundlach (1810–1896) conducted, while a resident of Cuba, two expeditions to Puerto Rico in 1873 and 1875–6, where he explored the southwestern, western, and northeastern regions of this island. Gundlach made representative collections of the island’s fauna, which formed the nucleus of the first natural history museums in Puerto Rico. When the natural history museums closed, only a few specimens were passed to other institutions, including foreign museums. None of Gundlach’s and few of his contemporaries’ specimens have survived in Puerto Rico. We located 191 bird specimens (43 species) collected there by Gundlach, all of which are in foreign institutions, especially Museum für Naturkunde Berlin. Here we list all located specimens and include data associated with them. Six new species were described out of the Gundlach collections from Puerto Rico, three of which are still taxonomically recognized today. Information about the types of those taxa is given.