Urinary glycosaminoglycan/creatinine ratio (GAG/Cr) was determined in 42 patients with superficial bladder tumors (before and after the treatment) and in 34 healthy subjects. Before the treatment, the mean GAG/Cr ratio in patients group was not significantly different from the control group's figure (11.65 +/- 3.25 and 10.11 +/- 2.67). However, comparison of urinary GAG levels of T-1, and Grade III tumors with the control group revealed statistically significant results (p < 0.01 and p < 0.001, respectively), All patients were previously operated by transurethral resection (TUR) and then intravesical chemotherapy applied [(BCG (n:20), 4-epidoxorubicin (n:12), interferon ar-l (n:10)]. Three months after the treatment, urinary GAG levels were determined in 19 of the 24 patients whose pretreatment urinary GAG levels were higher than the control group, tumor completely remitted and their urinary GAG excretion decreased. The tumor of the three, gradually progressed and their GAG excretions were normal. The two hadn't any tumor mass and their urinary GAG excretion was higher than the pretreatment levels. The remaining 18 patients didn't show any clinical modification and their urinary GAG excretion did not differ from the control's and pretreatment levels.