We have done a double-blind, randomized, controlled study on 37 patients with transitional cell carcinoma in which levamisole was used as an immune adjuvant in addition to the standard therapy for non-invasive and invasive bladder cancer. Levamisole is administered easily and is well tolerated, especially when compared to other immune adjuvants, such as bacillus Calmette-Guérin or Corynebacterium parvum. Recall antigens, dinitrochlorobenzene reactivity and total lymphocyte count demonstrated little correlation to the initial stage of disease. Monocyte chemotaxis was increased significantly in patients receiving levamisole. Since our study is ongoing no data exist as yet to make any statement regarding the efficacy of levamisole in the treatment of bladder cancer.