Fibropapillomatosis is a threat to the survival of marine turtles, especially green turtles; therefore, studies on this neoplastic disease are considered a conservation priority. Our goal was to characterize the incidence and spatial–temporal distribution of fibropapillomatosis in the Potiguar Basin, Rio Grande do Norte and Ceará states, Brazil. This study was based on data obtained during daily observations by a beach monitoring program from 2012 to 2015. A total of 2688 marine turtles, comprising the 5 species that occur in the Brazilian coast, were observed; 604 of the 610 individuals that presented fibropapillomatosis tumors were green turtles (Chelonia mydas). During the study period, we identified an increase in relative fibropapillomatosis frequency from 13.16% (2012) to 35.29% (2015), with a yearly peak in strandings between October and December. Fibropapillomatosis tumors were classified according to anatomical distribution, size, and the Southwest Atlantic Fibropapillomatosis Score (e.g., mild, moderate, and severe). The total number of tumors varied from 1 to 67; most were classified as size B and mild and were located mainly on the forelimbs and neck (49.63 and 25.95%, respectively). Our study shows the need to implement mitigation measures to promote sea turtle conservation in the Potiguar Basin, an important area for marine turtles in Brazil.