Introduction: Osteoclast-like giant cell bladder carcinomas are an extremely unusual and aggressive histological subtype of urothelial carcinomas. Only 30 cases have been reported globally. Clinical case: A 79-year-old male patient was presented to our Urology Department due to macroscopic hematuria that persisted for six months. As part of his diagnostic protocol, a CT scan of the abdomen and pelvis with elimination phase was performed, finding a filling defect of 12 mm at the level of the posterior wall of the bladder. A cystoscopy was subsequently performed, confirming the presence of a 1.5 cm bladder tumor, which was resected in its entirety. Pathology analysis with hematoxylin and eosin stain revealed a composition of mononuclear cells and osteoclast-like giant cells. Immunohistochemistry was positive for epithelial markers cytokeratins AE1/AE3, EMA, P53, and CD68. Conclusion: Osteoclast-like giant cell bladder carcinomas are extremely unusual and aggressive. The only diagnostic method is through immunohistochemistry, confirming the presence of epithelial markers for urothelium in the neoplastic cells. Radical surgical treatment is recommended and there has been no proven effective adjuvant treatment to date. The patients’ median survival is 15 months.