We report three cases of a primary malignant lymphoma of the urinary bladder. The radiological features revealed a sessile mass of the lateral wall for one case, a circumferential thickening in the second, and two separated masses of the bladder wall in the last case. Primary malignant lymphoma of the urinary bladder is extremely rare. From a review of the literature, the clinical and radiological findings are discussed. In this paper we report the first case of urinary bladder lymphoma presented on CTas multiple masses.