Background: One of the hardest problems in surgery is controlling face scarring, which is a challenging therapeutic issue for plastic surgeons to solve successfully. Nano fat injection under scar is expected to improve scar functionally and aesthetically. This study aimed to evaluate the effectiveness of Nanofat in improving the appearance of old facial scars using the Patient and Observer Scar Assessment Scale (POSAS) and clinical photographs. Methods: This prospective case series study was conducted at the Plastic and Reconstructive Surgery Department, in Zagazig university Hospitals, included 20 patients with variable types of face and neck scars. Scar revision was done in (3 patients) either by linear revision, multiple small Z-plasty or W-plasty after excision of the original scar. In the remaining 17 patients, Nano-fat injection of the old scars was done without scar excision. Results: In this study the most common site for harvested fat was (Abdomen in 15 patients), complication were minimal it was only in (25%) of total complication was occurred in scar site or donor site. We found that the POSAS scale for scar assessment, Evidently, there is marked improvement in the parameters of the score both individually ± in the final total score, P-values are found to be highly significant in all of them (P<0.01). Conclusion: The findings suggest that Nanofat injection, with its enhances neovascularization and extracellular matrix remodeling, can be an effective and safe treatment for reducing the appearance of old scars and enhancing their aesthetic quality.