Giant condyloma is a variation of condylomata acuminata caused by a sexually transmitted virus infection. Although it is a benign disease, it carries a risk of malignant transformation. Primary locations of giant condyloma are the perianal region and the external genitalia. Bladder involvement is rare. We report on a patient with multiple sclerosis in whom a giant condyloma developed in the bladder. Systemic immunosuppression for the treatment of multiple sclerosis and/or chronic cystitis as a result of neurogenic bladder dysfunction might be a risk factor for the development of giant condyloma of the bladder.