Purpose: To study those factors that influence the occurrence of surgical complications and local relapse in patients intervened for breast cancer and receiving intraoperative radiotherapy. Methods: Observational study on patients intervened for breast cancer with conservative surgery and intraoperative radiotherapy with low-voltage X-ray energy source (INTRABEAM), from 2015 to 2017 with 24 months minimum followup. Variables possibly associated to the occurrence of postoperative complications were analyzed with the Student t-test and the Fisher exact test; P < 0.05 considered significant. Subsequently, the construction of multiple multivariate analysis models began, thus building a logistic regression analysis using the IBM SPSS Statistics ver. 23 software. Local relapse was described. Results: The study included 102 patients, mean age of 61.2 years; mean global size of tumor, 12.2 mm. Complications occurred in 29.4%. Fibrosis was the most frequently observed complication, followed by postoperative seroma. Using a 45 mm or larger applicator were significantly associated with the occurrence of complications. Tumor size 2 cm or larger and reintervention showed borderline significant association. Only one case of local relapse was observed. Conclusion Certain factors may increase the risk of complication after the use of intraoperative radiotherapy. Using external complementary radiotherapy does not seem to increase the rate of complications. Select patients and the involvement of a multidisciplinary team are essential for achieving good results.