Although loop ileostomy as a diverting stoma has been considered to affect renal dysfunction, few reports have compared loop colostomy with loop ileostomy regarding renal function. This is an important issue in the current setting of increased opportunities to perform surgery on patients with poor renal function. This study aims to reveal the effect of ileostomy on renal dysfunction compared to colostomy following sphincter-preserving rectal surgery. This study was a retrospective analysis. We compared preoperative and postoperative blood urea nitrogen, serum creatinine and estimated glomerular filtration rate values. The study was conducted at a single academic institution in Osaka, Japan. From October 2013 to November 2021, 135 consecutive patients underwent rectal surgery with diverting stoma are included. Differences in pre- and postoperative renal function values by stoma creation site in patients with preoperative chronic kidney disease. Risk factors for patients with newly kidney disease after stoma creation. In the preoperative chronic kidney disease (+) patients, the differences between the pre- and post-values in the blood urea nitrogen (p = 0.047) and the serum creatinine (P = 0.028) values were higher than in the preoperative chronic kidney disease (-) patients. In the preoperative chronic kidney disease (+) patients, ileostomy was significantly associated with an elevation of the serum creatinine value (p = 0.025) and a decrease in estimated glomerular filtration rate value (p = 0.041) from the pre-operative one compared with that of colostomy. In multivariate analysis, ileostomy (odds ratio; 7.443, p = 0.011) and hypertension (4.226, p = 0.008) were independent risk factors of newly kidney disease postoperatively. Limitations to our study includes its retrospective nature and bias due to the stoma site being determined by each surgeon. We should take care to choose diverting stoma especially in patients with a risk of kidney disfunction. See Video Abstract.