The attempt was made in the dissertation to: 1. Evaluate the value of intraoperative and transcutaenous Doppler ultrasonography in prognosing delayed graft function (DGF), 2. Identify risk factors of DGF, 3. Assess the value of intraoperative and transcutaneous Doppler usg in detecting surgical complications of renal transplantation. It was shown in the studies that intraoperative and transcutaneous Doppler usg is easily available, non-invasive method used to detect blood flow in the renal allograft. Doppler usg with calculations of Resistive Index (RI) and Pulsatility Index (PI) is important prognostic factor for DGF. In the patients with renal allograft who developed DGF, mean values of RI and PI were 0.9 and 1.76, respectively and were significantly higher than in the patients without DGF. Diagnostic sensitivity of RI in prognosing DGF determined intraoperatively and in the first 24 hours after surgery was high, being 77.8% and 72.2%, respectively, and it was losing its diagnostic value on the next postoperative days. Diagnostic sensitivity of RI in prognosing DGF monitored intraoperatively and in the first 24 hours after surgery was comparable, and therefore it was not necessary to determine RI intraoperatively. Diagnostic sensitivity of PI in prognosing DGF in the first 24 hours postoperatively was the same as for RI, reaching 72.2%, and hence it was not necessary to control simultaneously both parameters. In the patients with the intraoperative RI higher or equal to 0.9 the risk of DGF was 13-fold higher compared with the patients whose intraoperative RI was lower than 0.9. Similarly, in the patients whose RI was higher or equal to 0.9 24 hours after surgery, the risk of DGF was 19-fold higher compared with the patients whose 24 hours after surgery RI was below 0.9. In the patients with the intraoperative PI higher or equal to 1.9 the risk of DGF was 12-fold higher compared with the patients whose intraoperative PI was lower than 1,9 and 24 hours after surgery it was 19-fold higher compared with the patients whose 24 hours after surgery PI was below 1.9. The analysis of other risk factors of DGF identified age of donors and volume of residual diuresis in the recipients as most important ones. Transcutaneous usg in detecting postoperative complications after renal transplantation has 93.8% sensitivity, 97.3% specificity, and 96.2% accuracy. The increase of RI over 0.9 and PI over 1.9 are important risk factors of renal vein thrombosis and renal artery thrombus in graft recipients.