Pleistocene marine conglomerates, first interpreted as alluvial-marine deposits, are attached to the walls of the valley of Agaete (NW of Gran Canaria), at 50-110 m above sea level. The deposits are 1 to 5 m thick, poor-sorted, clast-supported and formed by heterogeneous, angular to rounded, volcanic clasts and fossils, never found in growth position and often broken. The basal contacts show reaping features of the substratum and internally present two or more layers with reverse grading. Distribution, altitude and sedimentary structures of these deposits suggest that they were originated by tsunami waves, the most probable source being the Guimar giant landslide (east coast of Tenerife, <0,84 Ma)