Aim of the study: to evaluate the results of using intraoperative radiotherapy (IO RT) in patients with locally advanced rectal cancer (RC).Material and Methods. A total of 172 patients with histologically confirmed stage II –III (pT3–4 or pN+) RC were included in this retrospective analysis; of those, 92 (53,5 %) were treated with IO RT alone and 80 (46,5 %) received both neoadjuvant EBRT and IO RT. The median follow-up was 25 months for the IO RT group and 22 months for the EBRT/IO RT group (p=0,52).Results. The incidence of toxicity was low in both groups with an overall complication rate of 5,4 %. There were no statistically significant differences between both groups in 4-year overall survival rates (59,1 % in the IO RT group versus 67,4 % in the EBRT / IO RT group, p=0,66), progression-free survival (53,6 versus 55,1 %, p=0,51) and local progression free survival (59,4 versus 65,4 %, p=0,70).Conclusion. IO RT for locally advanced RC is a safe method that ensures adequate local control and can be considered as an effective treatment method both in an isolated version and in integration into a multimodal treatment algorithm in a specialized oncological clinics.