Hypertrophic scars and keloids are forms of abnormal wound healing. Both entities are the result of exuberant fibroblast response in the dermis. Nevertheless, their clinical and histopathological characteristics, as well as their pathogenesis, are differentThe aim of this study was to study the role of neuregulin- 1 in the pathogenesis of hypertrophic scars and keloids and studying the change in tissue expression after intralesional bleomycin injection. This prospective case - control study was carried on20patients who were suffering from keloids or hypertrophic scarsand were treated by intra lesional bleomycin injection, in addition to 20 apparently healthy individuals as a control group. Assement of hypertrophic scars and keloids before and after treatment byVancouver scar scale laboratory investigations including punch biopsies from hypertrophic scars, keloids and normal tissues, qRT-PCRfor gene expression of Neuregulin1 RNA was done. HTS group before treatment showed significantly higher level of neuregulin 1 but significantly lower after treatment and neuregulin 1 sensitivity was 80%, specificity was 100%,and accuracy was 90%.Neuregulin 1 before treatment showed significant positive correlation with Neuregulin 1after treatment.Better response was significantly associated with Lower baseline neuregulin 1.Higher neuregulin 1 was considered as risk predictor of HTS or keloid susceptibility and severity. Bleomycin usage has a better result and minimal complications and less recurrence rate, which shows its usefulness as the first-line treatment modality for management of keloids and hypertrophic scars.