Participation of anti-inflammatory interleukin-13 (IL-13) in the process of carcinogenesis was well studied. Angiogenesis plays a key role in the process of tumour growth and metastasis. Higher expression of angiogenin (ANG) have been proven in many types of cancers. The aim of the study was to more fully understand the significance of plasma IL-13 as an immunomodulator and ANG as a stimulator of the angiogenesis process in patients with bladder cancer (BC) and to investigate the relationship between parameters. These parameters were examined in the group of BC patients and in subgroups of BC depending on clinical stage: non-muscle invasive bladder cancer (NMIBC), muscle invasive bladder cancer (MIBC), histopathologic malignancy low grade (LG), high grade (HG) and in primary and recurrent BC. The level of IL-13 and ANG in the plasma of BC patients and controls were measured by enzyme-linked immunosorbent assay. All calculations were done using the STATISTICA 13.3 (TIBCO software Inc.). Plasma levels of IL-13 and ANG were significantly higher in BC patients and in all patient subgroups examined than in the controls (p < 0.001). A negative significant correlation was found between ANG and IL-13 levels in BC-patients. Based on the receiver operating characteristic curves (ROC), IL-13 had good diagnostic value in BC. The presented results may suggest a relationship between angiogenesis and inflammation in the pathogenesis of bladder cancer and the development of this disease. With the increase of IL-13 level in BC-patients plasma, the ANG level decreased.