Continuous insulin infusion was not an effective mode of treatment in maintaining safe blood glucose levels (<200 mg/dl) during the intraoperative period of diabetic patients requiring open-heart surgery. The two modifications investigated to gain better control of the blood glucose were a change in the base solution of the cardioplegia and the use of a sliding insulin scale. Fifty patients including Type I and Type II diabetics were selected for the purpose of this study. The patients were then randomly divided into two groups categorized by the type of cardioplegic solution administered and the mode of insulin treatment. Group I patients received a dextrose 5%-based cardioplegic solution and blood glucose was treated via continuous intravenous insulin infusion. Group II patients received normal saline 0.9%-based cardioplegic solution and blood glucose was treated via sliding scale. Blood glucose levels were monitored pre- and postcardiopulmonary bypass (CPB) and every 30 min while on CPB. Glucose values were analyzed by group t test. A p value of <0.05 was considered statistically significant. When comparing Group I (mean=258 mg/dl) with Group II (mean=158 mg/dl), there was a statistically significant difference between the glucose values at each of the time intervals when the glucose values were recorded. In conclusion, Group II maintained an acceptable blood glucose level (<200 mg/dl) throughout the entire intraoperative period, which suggests that the combination of the sliding insulin scale and modification of the base cardioplegic solution was an effective mode of treatment.