<p>Sicily, one of the largest Italian islands, was characterized by the presence of a Pleistocene insular fauna dominated by dwarf elephants and hippopotamuses. The remains of the latter, mostly attributed to <i>Hippopotamus pentlandi</i>, are relatively abundant and are recorded from over sixty paleontological localities. Despite its paleobiogeographic, paleoenvironmental, and evolutionary significance, there has been relatively limited focus on the hippopotamus specimens collected from Sicily, and in particular from the locality of San Ciro Cave (Palermo). This site has been known since the 16th century and preserves probably the most exceptionally rich hippopotamus assemblage of the whole island. This study presents an extensive review of the abundant postcranial remains from San Ciro Cave, which are currently stored in the Museo Geologico G. G. Gemmellaro of Palermo. Our morphological and morphometric comparisons reveal the occurrence of at least two distinct hippopotamus species in San Ciro Cave, <i>H. pentlandi</i> and <i>H. amphibius</i>. This finding suggests multiple colonization events or diachronic occurrences on the island. Peculiar morphological traits, such as robustness and enhanced cranio-caudal mobility in the distal limb bones, also reveal different environmental adaptations in the two species, suggesting a complex environmental mosaic in the area around the cave. Moreover, the body mass estimates of different hippopotamuses suggest that <i>H. pentlandi</i> was the heaviest insular Mediterranean species, followed by the smaller <i>H. melitensis</i>, <i>H. creutzburgi</i>, and <i>H. minor</i>.</p>