Intravesical therapy of superficial bladder cancer has been in routine use since the introduction of thiotepa in 1961. An empirical approach has been used to optimize this kind of treatment – clinical data are, unfortunately, often lacking. Marker lesion studies indicate that BCG is more effective than cytostatic drugs. For the prophylaxis of recurring disease, the recurrence rate is lower with chemotherapy than in controls, but no effect on the risk of progression has been verified. None of the chemotherapy drugs used has proved superior to the others. Randomized trials have recently been performed with mitomycin C vs. BCG. Comparison of the different trials is difficult due to the use of different methodologies. The majority of the studies found BCG to be more effective in lowering the number of recurrences, but progression rates were not significantly different. Trials with combinations of BCG-mitomycin C or epirubicin-interferon have yielded promising results.