Background and Clinical Significance: Cladosporium cladosporioides is a ubiquitous dematiaceous mold that is rarely implicated in invasive human diseases and often considered a saprophyte and plant pathogen. Case Presentation: We report an extremely rare case of C. cladosporioides fungemia in a 61-year-old man with mantle cell lymphoma undergoing chemotherapy. The patient developed fever, dry cough and cavitary pulmonary lesions in the setting of profound immunosuppression. Blood cultures yielded slow-growing dark pigmented mold after prolonged incubation and species identification was achieved using MALDI-TOF mass spectrometry with an alternative fungal database, supported by microscopic morphology. Serum 1,3-β-D-glucan levels were markedly elevated, while galactomannan antigen testing was negative. Antifungal susceptibility testing demonstrated activity of triazoles and targeted therapy with voriconazole led to clinical improvement. A review of the literature identified only five previously reported cases of invasive C. cladosporioides infections worldwide, involving primarily pulmonary and central nervous system disease. Conclusions: To the best of our knowledge, this is the first documented case of fungemia caused by this species. The current report highlights the pathogenic potential of C. cladosporioides in immunocompromised hosts, the diagnostic challenges posed by slow-growing dematiaceous fungi, the importance of prolonged culture incubation, fungal biomarkers and advanced identification techniques for timely diagnosis and management.