The contents of urokinase-type plasminogen activator were estimated in superficial bladder cancer from 42 patients undergoing transurethral resection for the first time. Tumor recurred in 11 of 16 patients (68.8%) with high urokinase-type plasminogen activator content (8 ng. urokinase-type plasminogen activator per mg. protein and more) and in 12 of 26 (46.2%) with low urokinase-type plasminogen activator content. In the high content group 8 patients (50%) had disease progression compared to 2 (7.7%) in the low content group (p < 0.01). The progression rates in the high urokinase-type plasminogen activator group with stage pTa disease or tumors more than 1 cm. large were significantly higher than those in the low urokinase-type plasminogen activator group (p < 0.05). The recurrence and progression rates in the high content group with stage pT1, grades 2 and 3, single and multiple tumors, and tumors less than 1 cm. large were higher than those in the low content group. The progression-free survival rate in the high content group was significantly lower than that in the low content group (p < 0.005). In conclusion, urokinase-type plasminogen activator content may be a useful marker to predict recurrence and progression of superficial bladder cancer.