A dark-coloured trace fossil assemblage from the Cretaceous/Palaeogene (K/Pg) boundary interval in the Agost section (Betic Cordillera, south-east Spain) has been examined. These trace fossils, of early Danian age, are located within host Plummerita hantkeninoides Biozone (Late Maastrichtian) sediments. The assemblage consists of Chondrites ?targionii, Zoophycos isp., Planolites isp. (two size classes), ?Thalassinoides isp. A, T. isp. B, T. isp. C, Alcyonidiopsis longobardiae, and Diplocraterion ?parallelum. The latter two species are described here for the first time within K/Pg boundary intervals. Major differences in trace-fossil composition between the Agost and other K/Pg boundary sections (Denmark, Alabama and north-east Mexico) can be related to palaeoenvironmental factors, mainly reflecting the more distal and deeper environment of the Agost section.