Scedosporium/Lomentospora is an opportunistic fungal pathogen found worldwide. While Scedosporium apiospermum and Scedosporium boydii are commonly observed globally, Lomentospora prolificans, which mainly affects immunosuppressed individuals, is rarely encountered and is more prevalent in arid climates, particularly in Australia and Spain. L.prolificans is a fungus commonly found in environmental sources such as contaminated water and soil. This species is known as an opportunistic pathogen that can cause deep-seated fungal infections, especially in immunosuppressed individuals. In this case report, a fatal case of L.prolificans fungemia in a patient with T-cell large granular leukemia during profound neutropenia was presented. The patient admitted to the hospital with prolonged fever, neutropenia, and shortness of breath. Antibiotherapy was administered to the patient for febrile neutropenia, but the fever persisted and his clinical status rapidly deteriorated. L.prolificans was isolated from the blood culture, and considering its antifungal resistance, combination therapy of voriconazole and terbinafine was initiated. However, the patient died of septic shock and multiple organ failure. In conclusion, although L.prolificans infections are rare, they can be life-threatening, especially in immunosuppressed individuals. Diagnosis and treatment of such infections may be difficult, therefore rapid diagnostic methods and appropriate treatment protocols should be developed. Consideration of infections caused by rare fungal pathogens in patients with risk factors may be critical for patient care. The literature review revealed that the first case of L.prolificans fungemia from Türkiye was reported in 2023. This case presentation represents the second reported case. However, in our case, L.prolificans fungemia occurred in 2018, it can be considered that L.prolificans may have been an invasive fungal pathogen of significant concern in Türkiye much earlier than previously documented.