Objective: Ureteral injury is a typical complication in pelvic surgery even though occurring not frequently. The goal of this study was to classify the importance of perioperative assessment of serum creatinine with clinical symptoms concerning the early detection of ureteral lesions after surgery. Patients and methods: The postoperative course of 7 gynecological and 2 obstetric patients raising doubt on ureteral integrity was analyzed, retrospectively, using medical records. Clinical symptoms (urinary production, flank pain), and the temporary changes of serum creatinine (µmol/L) as well as interdisciplinary diagnostic and interventional procedures were recorded. Glomerular filtration rate (GRF) was calculated using CKD-EPI formula (mL/min/1.73m2). Data analysis was done using descriptive statistics, Fisher’s exact test, non-parametric tests, and regression analysis (SPSS). Results: 6/9 patients presented with ureteral impairment. In 5/6 patients unilateral (n=2) and bilateral (n=3) obstructions were detected all deriving from anterior colporrhaphy. 1 patient exhibited ureteral kinking healing spontaneously. In patients affected by ureteral obstruction diminishing of urinary outflow occurred significantly earlier than flank pain (2.8±1.0 vs. 28.8±9.2 hours, p=0.03). Mean increase in serum creatinine and decrease of GFR was from 72±16 before surgery up to 160±34 and from 79±18 down to 30±6 (p=0.07), respectively, within 8–48 hours after surgery being significantly different from respective values in patients without obstruction (p=0.03). The increase in creatinine in patients with unilateral obstruction followed a logarithmic graph indicating interference between deteriorated ipsilateral and functionally compensating contralateral kidney after 24 hours. Conclusion: Perioperative measurement of serum creatinine is useful in testing ureteral integrity. However, the negative predictive value is superior to the positive predictive value. According to decreasing GFR highly important is a contemporary registration of the urine outflow in the first hours after surgery.