Despite the potential advantages of a preventive intestinal stoma after the formation of a low colon anastomosis during rectal resections, the formation of a preventive loop ileostomy is associated with a significant frequency of complications. OBJECTIVE: To determine the potential prognostic factors of complications associated with ileostomy dysfunction in patients who have undergone rectal resection for cancer. MATERIAL AND METHODS: We retrospectively analyzed patients over the age of 18 who underwent open and laparoscopic resection of the rectum with the formation of a preventive ileostomy from January 2015 to May 2022. To determine the influence of potential predictors on the frequency of complications associated with large ileostomy losses, a single-factor logistic regression analysis was used. Complications associated with large ileostomy losses were primarily water-electrolyte disorders, dehydration and acute renal failure, which required intensive therapy and re-hospitalization. RESULTS: Of the 120 patients included in the study, 26 (21.7%) suffered complications associated with large losses of fluid and electrolytes in the stoma. In this group of patients, at least one repeated emergency hospitalization to a medical institution was required (average value 1.6). Factors associated with ileostomy dysfunction in a single-factor analysis were: the presence of signs of intestinal obstruction (OR=2.6; p=0.047), the development of postoperative complications (OR=3; p=0.024), steroid use (OR=4.3; p=0.010), smoking (OR=4.8; p=0.017) the average amount of discharge from the stoma at discharge is more than 1000 ml/24 h (OR=3.2; p=0.016) and the need for Loperamide at the time of discharge (OR=2.8; p=0.032). Multivariate logistic regression analysis revealed an independent risk factor for complications leading to re-hospitalization: ileostomy losses at discharge ≥1000 ml/24 h (OR=3.3 (1.18-9.37); p=0.023). CONCLUSION: In our study, those patients whose ileostomy discharge exceeded 1000 ml/24 h at discharge were at increased risk of dehydration, hypokalemia, hypocalcemia, acute prerenal renal failure, which led to repeated hospitalization to correct these disorders, sometimes in the intensive care unit.