Aim: Retrospective Comparative Analysis of Frozen and Subcutaneous Bone Flap Storage Methods for Autologous Bone Cranioplasty. Material and methods: A retrospective study was conducted, authorized by the institutional review board, to identify all adult patients who had autologous bone cranioplasty after craniectomy. we examined the electronic medical records of these patients to gather various demographic information such as sex, race, and age. They also collected baseline characteristics including smoking status and body mass index (BMI). Additionally, we recorded any medical conditions the patients had, such as osteoporosis, diabetes, and a history of cancer, as well as other conditions like chronic obstructive pulmonary disease, hypertension, congestive heart failure, peripheral vascular disease, stroke (hemorrhagic and ischemic), myocardial infarction, coronary artery disease, coronary artery bypass grafting, and chronic kidney disease. The Glasgow Coma Scale score before and after surgery, as well as the modified Rankin Scale score before and after surgery, were also recorded. Furthermore, the charts were used to determine various acute surgical complications such as hospital-acquired infection (HAI), surgical site infection, deep vein thrombosis, pulmonary embolism, hematoma, and cerebrospinal fluid leak. Results:The duration of follow-up for the 40 patients who had subcutaneous storage was 443.45± 25.78 days, whereas it was 355.76± 15.76 days for the patients who underwent frozen storage. The two groups had comparable baseline characteristics, with the exception of BMI, which showed a statistically significant difference when comparing both demographics and comorbidities (Tables 1 and 2). The average BMI of the population stored in frozen bone (27.87 ±3.57) was significantly higher (P = 0.02) than the population stored subcutaneously (24.77 ±3.76). The time of surgery for cranioplasty utilizing bone kept in the belly (182.71±8.87 minutes) was substantially greater (P < 0.001) compared to surgeries using autologous bone preserved in the freezer (114.64 ± 7.66 minutes). The only other significant difference (P = 0.02) was observed in the placement of a ventriculoperitoneal shunt (VPS). The subcutaneous storage population had a much higher occurrence of VPS placement during the cranioplasty procedure (42.4%) compared to the frozen storage population (11.67%). However, VPS placement before the cranioplasty procedure (in a separate procedure) was more common in the frozen storage population (23.33%) than in the subcutaneous storage population (10%). Conclusions: Both subcutaneous and cryopreservation are viable and possibly comparable choices for storing the bone flap after craniectomy.