The dataset presents the number of mesopelagic Decapoda collected during the CSIC-SUMMER survey carried out in October 2010 in five zones around the Iberian Peninsula: south of Balearic Islands and Alboran Sea in the western Mediterranean, and Gulf of Cadiz, off Lisboa and off Galicia in the Atlantic. The scientific midwater trawl Mesopelagos (Meillat, 2012) fitted with the VERDA Multisampler (Castellón and Olivar, 2023), placed at the end of the net, was used to collect specimens at seven layers of the water column. The depth of the net was controlled by a SCANMAR system. In the five zones hauls were carried out day and night to study vertical distribution and migration patterns. Samples covered between 0 and 700 m, and discriminated seven layers in the water column. This file presents numerical abundance by taxa, generally to species level in the different hauls performed. These data were obtained within the European Union Project 'Sustainable Management of Mesopelagic Resources' (SUMMER, Grant Agreement 817806) as funded by the Horizon 2020 Research and Innovation Programme.