Fibropapillomatosis (FP) is characterized by multiple fibroepithelial tumors in all parts of the skin and has been reported in sea turtles worldwide. Clinically infected individuals are often emaciated and anemic. In Mexico, however, there are few records of this disease. In this study of green turtles Chelonia mydas in Laguna San Ignacio in Baja California Sur (BCS), we noted one juvenile with multifocal fibropapilloma lesions on the external upper surface of its eyes and hind flippers. Light microscopy revealed hyperkeratosis, epidermal hyperplasia, dermal papillary projections, and fibroblast proliferation. Electron microscopy revealed viral particles. Biopsies of normal skin were done to determine the origin of the turtle through genetic analysis. Its mitochondrial DNA matched that of a haplotype (CMP2) from a Hawaiian green turtle population. Finding FP in a turtle captured in BCS elucidates the need for further monitoring along the west coast of Mexico. Further investigation should include testing tumors to detect and characterize any chelonid herpesviruses and explore any association with FP and other diseases that pose a health risk to other sea turtle species. Received March 26, 2016; accepted August 3, 2016.