During cardiac surgery, cardioplegia is the method used to stop and protect myocardial function. A crucial strategy for minimizing myocardial problems during and following cardiac surgery is myocardial protection. The study's objective is to evaluate the postoperative prognosis in patients having various difficult cardiac surgeries by contrasting Custodiol with cold crystalloid-enriched blood cardioplegic solution. The study was carried out in Alzahraa university hospital and Ain Shams university Hospital from (February 2022) to (October 2022). A total of 40 patients underwent different complex cardiac surgery using cardiopulmonary bypass aged 21 to 65 years, ASA class II-III was randomly assigned to either the Custodiol single dose (group1, n =20) or the traditional blood cardioplegic solution (group2, n =20) to induce cardiac arrest. Need for inotropic support was more significant in group 2 than in group 1. How ever, there was no statistically significant difference between either group with respect to the number of patients who required inotropes, those who had AKI and the length of ICU stay. When compared to cold blood cardioplegia, a single dose cardioplegia method (Custodiol) for myocardial protection offers the benefit of not requiring repeated administration.