INTRODUCTION Obesity is a growing worldwide problem. One of the most effective treatments is a bariatric procedure; however, surgery is associated with the risk of complications, such as staple line leakage, suture line bleeding, and rhabdomyolysis (RML). OBJECTIVES The objective of our study was to assess the risk of RML after bariatric surgery related to intravenous fluid administration in the perioperative period. PATIENTS AND METHODS The study involved 194 patients who underwent a bariatric surgery (laparoscopic sleeve gastrectomy or laparoscopic gastric bypass). We studied an association between the development of RML and sex, age, weight, duration of surgery, type of surgery, and the volume of intravenously administered fluids during the perioperative period. RESULTS The median duration of surgery was 132.5 minutes. The median volume of administered fluids was 3150 ml from the introduction of anesthesia to 24 hours after surgery. Biochemical RML (creatine phosphokinase >1000 U/l) was observed in 30 patients (15.46%). RML with clinical manifestations developed in 6 patients. Multivariate logistic regression revealed an increase in the odds ratio of biochemical RML with an increase of weight on the day of surgery, operative time, and volume of intravenous fluids. A multiple regression model showed that every 500 ml of transfused fluid over the median volume increases creatine phosphokinase concentrations in the first postoperative day by 241.77 U/l over the median level, with the operative time and patient's weight remaining at median values. CONCLUSIONS We observed an association between the administration of lower fluid volumes and a lower risk of RML. We postulate that decreasing intravenous fluid administration may reduce the risk of RML after bariatric surgery.