Background: Coronary artery bypass grafting (CABG) is a surgical option for patients with significant coronary artery disease (CAD) who are not suitable candidates for percutaneous interventions. Cardiopulmonary bypass (CPB) with cardiac arrest (on-pump) provides a surgical field free of motion and blood, allowing safe anastomosis construction. Off-pump CABG (OPCABG) avoids serious complications associated with CPB such as stroke, renal dysfunction, and systemic inflammatory response syndrome. Intravenous fluids are administered to maintain the circulation blood volume and cardiac output during surgical manipulation of the heart during OPCABG. This study was performed to compare the effects of Ringer's lactate (RL) and Plasmalyte® (PL) on the acid base status and electrolyte balance in patients suffering from type-2 diabetes mellitus (T2-DM) undergoing elective OPCABG surgery. Methods: After obtaining ethical approval and informed consent, this study was performed on patients with type-2 DM undergoing elective OPCABG. Patients undergoing CABG on CPB, concomitant procedures, emergency, renal dysfunction, conversion to CPB were excluded. OPCABG was performed as per the standard institutional protocol. Intraoperative management of DM was done using recommended guidelines namely maintenance of blood sugar between 140 and 180 mg% and insulin infusion titrated to achieve the blood glucose in the desired range. Serum potassium was maintained between 4 and 5 mmol/L. Arterial blood gases and lactate levels were determined at two hourly intervals throughout the perioperative period. Comparison of serum lactate levels, base deficit levels, potassium levels, and pH values was done by paired t-test. Outcome measures included low-output state, renal dysfunction, bleeding, tracheotomy, ICU stay, hospital stay, and mortality. Results: There were 50 patients in the group with 25 in each group. None of the patients was converted to on-pump and complete data were available to all patients. At 12th postoperative hour, lactate was significantly lower (p < 0.014) and serum potassium levels were significantly higher (p < 0.018) in PL group. When compared to the PL group, the base excess levels were significantly higher (p < 0.035) in ringer lactate group at 24th postoperative hour. Excepting for this, there were no significant differences in any of the measured parameters, outcomes, length of ICU stay, and hospital stay in the two groups. Conclusion: In well-controlled patients of type-2 DM with precise perioperative monitoring and management of blood glucose and serum potassium, there were no significant differences in outcomes between RL and PL in diabetic patients undergoing OPCABG.