Objective: To compare the histological responses of 3 bulking agents, which are used in the endoscopic treatment of vesicoureteral reflux, on rats’ urinary bladder and subcutaneous tissue. Materials and Methods: Thirty rats were divided into 3 groups according to the injection materials; Dextranomer Hyaluronic acid- Deflux® (DxHADf), Dextranomer Hyaluronic acid- Deal® (DxHA-Dx) and Polyacrilate Polialcohol Copolymer-Vantris® (PPC). In each group, material was injected both into the submucosa of the rats’ urinary bladder dome and the subcutaneous tissue at their names. In each group, 5 rats were scarified at the 2nd and 6th months after injection. The histopathologic compartment was performed by scoring inflammation, neutrophil, eosinophil, macrophage, mast cell and giant cell reactions around the injected material. Results: All materials maintained their bulky effect. Despite the large amount of degradation with dextranomer materials, there was minimal degradation with PPC. The materials had the same amount of capsule formation around the injection site, which was not related to the degradation properties of the material. There was no statistically significant result for bladder injections. For subcutaneous injections mast cell scores around the injection (DxHA-Df, DxHA-Dx, PPC: 1.4, 1.2, 0 respectively, p=0.024) were significantly different at 2nd month. Mast cell scores around the injection (DxHA-Df, DxHA-Dx, PPC: 1.0, 1.75, 0 respectively, p=0.007) were significantly different at 6th month also. The inflammation around PPC was higher at the 6th month (DxHA-Df, DxHA-Dx, PPC: 1, 1, 3.5 respectively, p<0.05). Conclusion: Both dextranomer agents were degradable with good capsule formation and minimal inflammation in the adjacent tissue. PPC degraded minimally and caused significant inflammation at adjacent tissue.