Objective: to determine the diagnostic value of nerve growth factor (NGF) and C-reactive protein (CRP) in patients with interstitial cystitis / painful bladder syndrome (IC/BPS).
 Material and methods. 44 patients with IC/BPS (main group) and 20 volunteers (control group) were examined. The average age of the patients of the main group was 46.4 13.9 years, the control group 35.3 9.7 years. Cystoscopy and hydrodistension of the bladder were performed. The severity of pain was evaluated on a visual analogue scale (VAS). The concentration of NGF was determined in the blood by the method of ELISA, CRP by the immunoturbidimetric method.
 Results. The average total score on the VAS scale was 5.47 0.91, mild pain (24 points) was noted by 20.4%, moderate pain (56 points) 54.5%, severe pain (78 points) 25.0% of patients. Diffuse bleeding of the bladder mucosa in 45.4% of cases was observed. In IC/BPS patients the average NGF level was 11.23 8.22 ng/ml, CRP 3.56 1.66 mg/l. The concentration of NGF exceeded the control level by 22.7% (p 0.05), CRP by 71.3% (p = 0.015). The correlation coefficient of NGF with CRP was r = + 0.179 (p = 0.42), and the determination coefficient was R2 = 0.032.
 Conclusion. Identified statistically significantly increased levels of NGF and CRP in the blood serum of IC/BPS patients confirm the presence of a systemic inflammatory reaction. A weak direct correlation is determined between NGF and CRP in patients with IC/BPS patients. The determination of serum NGF and CRP in combination with clinical data can be used to diagnose IC/ BPS.