This cross-sectional observational study was performed to evaluate the post-operative electrolyte imbalance in oral squamous cell Carcinoma patients, and it was conducted at the Department of Oral & Maxillofacial Surgery in Dhaka Dental College & Hospital, Dhaka, Bangladesh during June 2022 to June 2023. A total of 100 patients who were clinically and histo-pathologically diagnosed as OSCC patients were enrolled in this study. The collected data were edited, coded processed for computer data entry. The data were analyzed using Statistical Package for Social Sciences (SPSS) software, version-23.0. Descriptive analysis was performed and the results were presented as tables and graphs. Unpaired t tests, Chi-square, Spearman’s rho correlation tests were performed to compare the mean and ratio correlation of the study variables where P<0.05 with 95%CI. The ethical clearance of this study was obtained from the Ethics Committee of Department of Oral & Maxillofacial Surgery in Dhaka Dental College & Hospital, Dhaka, Bangladesh. A total of 100 oral squamous cell carcinoma (OSCS) patients were enrolled in this study. The mean age of the patients was 56.63 ± 9.54 years. The mean BMI of the patients was 18.20 ± 0.60 kg/m2. The majority of the patients were male and it was 54% while female was 46%. 64% patients belonged to lower socio-economic class. 52% patients had the habit of betel nut which was the highest while 39 % had the habit of betel nut with tobacco. The majority, 32% of patients had Stage-I. The mean surgery duration was 5.45± 0:91 hours and 7.2±: 0:15 minutes. The mean blood required for the surgery 1.44±0.68 units. According to the distribution of the post-operative variations of electrolyte imbalances, Sodium (Na+) was observed, hypo 25(25%) and hyper0(0%) on day-1 and hypo 31(31%), and hyper 4(4%) was observed on day 3 and followed by Potassium (K+) hypo 5(5%) and hyper 2(2%) on day- 1 and hypo 7(7%) and, hyper2(25) on day- 3. In comparison of ratio between hypo and hyper of day1 and day-3, showed statistically significant relationship observed (p<0.05). According to postoperative electrolyte distribution, on day-1, mean Sodium (Na+) was observed 136.68±2.69 mmol/L whereas on day-3, mean Sodium (Na+) was observed 133.81±4.21 mmol/Land followed by on day-1 mean Potassium (K+),3.86±0.46mmol/L, day-3, mean Potassium (K+),3.74 ±0.45 mmol/L on day-1. Among the postoperative electrolyte, except, Potassium (K+), all were observed statistically significant (P<0.05). In conclusion, hypocalcaemia, hyponatremia, and hypomagnesaemia are the relatively common after maxillofacial surgeries. Beside this BMI could affect electrolyte abnormalities after maxillofacial surgery.