This work was carried out on three groups, 30 Egyptian patients with Schistosoma haematobium (S. haematobium) with bladder cancer (15), and without bladder cancer (15), as well as 15 normal individuals as a control. All the individuals were subjected to measurement of serum level of GST by using ELISA technique and genotyping for GST-M1 & GST-T1 using PCR technique. The results proved that GST serum level was significantly deceased in S. haematobium patients with bladder cancer as compared to the other groups. The PCR results for the GST-M1 & GST-T1 genotyping showed 4 categories, (M1+ve/T1+ve, M1+ve/T1-ve, M1-ve/T1+ve, M1-ve/T1/-ve). There was a significant decrease in enzyme levels in patients with GST-M1-ve/T1-ve as compared to the other categories. Besides, there was a significant increased risk for bladder cancer development in patients with combined gene deletion (OR = 40) which represented mainly in S. haematobium patients with bladder cancer (53.3% = M1-ve/TI-ve).