Background and Aim:Bladder tumor is one of the most common genitourinary tumors. Management of non-muscle invasive (NMI) bladder tumors is primarily by transurethral resection (TURBT) followed by intravesical immunotherapy or chemotherapy. Bacillus Calmette-Guerin (BCG) is the most effective adjuvant therapy in NMI bladder tumor. Since angiogenesis is an essential factor in solid tumor progression and vascular endothelial growth factor (VEGF) is an important factor in angiogenesis, the aim of this study is the assessment of angiogenic factor, VEGF, serum and urine level changes in superficial bladder tumor immunotherapy by intravesical BCG.Materials and Methods:A total of 23 patients with bladder transitional cell carcinoma (TCC) in stage Ta/T1 or carcinoma insitu (CIS), low or high grade, which passed a 2-4 week period from TURBT participated in this study. Blood and urine samples were obtained at first and sixth sessions before instillation of BCG. Enzyme-linked immunosorbent assay (ELISA) method was used to obtain VEGF level in samples.Results:Urine and serum VEGF levels did not change significantly before and after BCG therapy. Changes in VEGF level were significantly different neither in low grade against high grade tumors nor in stage T1 against stage Ta tumors. A significant difference in VEGF level was seen between low grade and high grade tumors in serum after BCG therapy (P=0.007); but not in urine samples.Conclusion:Although intravesical BCG possesses anti-angiogenic activity, it seems that it exerts its effect through pathways other than VEGF, especially in low grade tumors.