The conservation of the portal representing the Nativity and the Baptism of Christ in Sevilla’s Cathedral, attributed to the architect Charles Gauter de Ruan, had as its objective the preservation of both the original parts and those historical additions which did not represent a danger to the supporting materials. A maintenance plan was developed according to the diagnosis of the monument’s deterioration process, the measures adopted to stabilize it, the potential risks it will face and the possibility of controlling them. Once the incidence of each deterioration factor is assessed, regular inspections will be established to detect new damages. According to the results of these inspections, future actions will be planned to avoid the progressive deterioration of the portals. -- SCMRE