120 patients with the first occurrence of TNM stage Ta or T1 bladder carcinoma were given adjuvant intravesical treatment in 2 consecutive series. The first 60 received doxorubicin monthly for 6 months, then on the 9th and 12th month following surgery. The second series was given mitomycin weekly for 2 months, then monthly to the end of the first year. Median follow-up is 48 months in the first series and 15 in the second. In the doxorubicin group, 28 patients had recurrences. The recurrence rate is 1.86/100 patient-months. Seventeen of these first relapses occurred within the first year. In the 'intensive' mitomycin series, where 36 patients were observed for 12 months or more, 3 relapsed. The recurrence rate to date is 0.35. The relapse-free survival probability at 12 months is 75% in the first series and 93% in the second. Treatment was stopped due to toxicity in 4 patients in the doxorubicin group and in 10 of the mitomycin group.