Aim: To assessment of alterations in serum potassium levels during postoperative exploratory laparotomy. Materials and methods: This was a prospective study conducted in the Department of General Surgery, Indira Gandhi Institute of Medical Sciences, Patna, Bihar, India for two years. A total of 50 patients who underwent explorative laparotomy were included in this study. Collection of 2 cc of blood volume was done at preoperative time, one the day of surgery and on postoperative days of surgery. All the samples were sent to laboratory where autoanalyzer was used for assessment of serum potassium levels. Results: In the present study, a total of 50 patients who underwent exploratory laparotomy were included. Mean age of the patients was 59.4 years. 66 percent of the patients were males while the remaining were females. Mean potassium levels at Baseline (before starting of surgery), one day after surgery, three days after surgery and seven days after surgery were found to be 4.73 mEq/L, 5.33 mEq/L, 4.52 mEq/L and 4.43 mEq/L respectively. Conclusion: A significant reduction in the potassium levels during the initial postoperative phase was seen followed by a significant rise; thereby returning to normal value 1 week postoperatively