Abstract : Microvascular free tissue transfer has gained popularity throughout the years. Many plastic surgery centers perform such challenging surgery on patients requiring extensive defect closure, including our center in the last five years. We will review our previous cases in order to achieve and assess our learning curve in a developing country. In this case series study, we looked at all patients who had a microvascular free tissue transfer conducted by a single operator (PA) in one institution between 2014 and 2018. Multivariate analysis was conducted to find out factors involved in free flap failure, which were age, gender, BMI, an indication of surgery, location of the defect, type of flap, number of veins anastomosed, vein graft usage, length of hospital stay, length of intensive care unit stay, and perioperative complications. Then, 203 microvascular tissue transfers were performed to reconstruct and close defects of various anatomic locations by a single operator. The patients' age ranged from 5.5 to 79 years. Most defects were due to tumor ablation, besides trauma and congenital deformity. The microvascular free flap reconstruction of various kinds of indications all over the body showed a viable flap rate of 90.6%. We concluded that to achieve a consistent high success rate, the parameters impacting the flap's viability must be evaluated regularly. This study found that the flap's viability can be affected by the number of veins anastomosed, BMI, length of hospital stay,