Scladina Cave, a key Middle Paleolithic site in Belgium, has yielded the earliest documented evidence of Neanderthals using cave lion bones as tools. This study focuses on stratigraphic Unit 5 (MIS 6), where four bone retouchers were identified. The diaphyseal fragment of the tibia reconstituted using two of the retouchers shows prior use as an intermediate tool (chisel) before being deliberately fractured and each of the fragments used separately as a retoucher. These tools display typical use-wear patterns made on fresh bones. ZooMS and LC-MS/MS analysis confirmed their identification as cave lion bones. Despite their well-documented coexistence and likely competition, evidence of interaction between these two predators is rare. The deliberate exploitation of cave lion remains at Scladina Cave suggests a complex relationship between Neanderthals and large carnivores. This behavior parallels their exploitation of cave bears, evidenced by anthropogenic modifications. The presence of cut marks and intentional modifications on relatively fresh carcasses indicates that Neanderthals knowingly utilized remains of their ecological competitors.