Background and aims Pancreatic walled-off necrosis (WON) carries significant mortality and morbidity risks, often necessitating intensive care unit (ICU) admission. This retrospective study aimed to evaluate whether routine biochemical parameters at the time of the index endoscopic procedure could predict ICU admission and 1-year mortality following endoscopic treatment of WON. Materials and Methods We retrospectively identified 201 consecutive patients who underwent endoscopic drainage for WON between January 1, 2010, and December 31, 2020. Associations between routine biochemical blood tests and outcomes were assessed using logistic regression models. Results Within 1 year of the index endoscopy, 31 patients (15.4%) died, and 40 (19.9%) were admitted to the ICU due to sepsis. Preoperative electrolyte disturbances were more prevalent among ICU-Admitted patients and nonsurvivors. Hyperkalemia, hypoalbuminemia, and elevated urea were significant predictors of 1-year mortality, while hypernatremia, elevated serum creatinine, and hypoalbuminemia predicted ICU admission. Predictive models exhibited good discriminative ability, with an AUC of 0.84 (95% CI,0,75-0.93) for 1-year mortality and 0.86 (95%CI, 0.79-0.92) for ICU admission. Conclusions Preoperative imbalances in routine blood tests effectively predict adverse outcomes in endoscopically treated WON patients.