Melanosis vesicae (or bladder melanosis) is a rare, benign condition referring to the presence of dark pigmented melanin deposits usually within the bladder mucosa. The clinical presentation can be mistaken for primary or metastatic melanoma of the bladder, and thus a histologic assessment is useful for ruling out a malignant diagnosis. All documented cases of melanosis vesicae have presented with urinary symptoms, including hematuria, symptoms of cystitis, incontinence and obstruction. This is a case report presenting a 57-year-old female with complaints of incomplete bladder emptying who met criteria for urinary retention. She underwent in-office cystoscopy and was found to have suspected melanosis vesicae. The diagnosis was later confirmed on pathology following a bladder biopsy. The next phase in care for this patient is planned sacral neuromodulation for treatment of urinary retention. Previous case reports of bladder melanosis have suggested an association with melanin deposition and inflammatory mechanisms and have not demonstrated malignant transformation during follow up. This is, to our knowledge, the first report of documented bladder melanosis in conjunction with urinary retention. Further studies are required to understand the etiology, clinical significance, and clinical correlation of melanosis vesicae with urinary dysfunction.