Aphid species from 11 of the major islands of Micronesia ranging from Majuro, Republic of the Marshall Islands, in the east to Koror and Babeldaup, Republic of Palau, in the west, are documented based on 1,691 collections. Other islands sampled included Yap, Kosrae, and Chuuk in the Federated States of Micronesia; Saipan, Tinian, and Rota in the Commonwealth of the Northern Mariana Islands; and the Territory of Guam. Host-plant associations were documented at each collection site. Thirty-five aphid species were collected from 139 plant species in 43 different plant families. None of the aphids collected is indigenous to Micronesia. A key to the identification of the aphid species is provided.