Purpose. Rhabdomyolysis (RML) following cardiac surgery and its relationship with acute kidney injury (AKI) require investigation. Patients and Methods. All patients undergoing cardiac surgery in our hospital were enrolled in this prospective study during a 1-year period. To investigate the occurrence of RML and its association with AKI, all patients in the study underwent serial assessment of serum creatine kinase (CK) and myoglobin levels. Serial renal function, prior statin treatment, and outcome variables were recorded. Results. In total, 201 patients were included in the study: 185 men and 16 women with a mean age of 52.0 ± 12.4 years. According to the presence of RML (CK of ≥2,500 U/L), the patients were divided into Group I (RML present in 17 patients) and Group II (RML absent in 184 patients). Seven patients in Group I had AKI (41%) where 34 patients in group II had AKI (18.4%), P = 0.025. We observed a significantly longer duration of ventilation, length of stay in the ICU, and hospitalization in Group I (P < 0.001 for all observations). Conclusions. An early elevation of serum CK above 2500 U/L postoperatively in high-risk cardiac surgery could be used to diagnose RML that may predict the concomitance of early AKI.