Acne vulgaris is a chronic cutaneous inflammatory disorder. Four factors play vital roles in acne pathophysiology: hyperseborrhea , altered keratinization of the pilosebaceous duct, propionobacterium acnes (p. acnes) and inflammation. to assess serum level of follistatin in patients with scarring and non scarring AV aiming at understanding the pathogenesis of post acne scars. serum FST level was assessed in 60 acne patients (30 non scarring patients - 30 scarring patients) and 20 apparently healthy subjects as control  with matched age and sex. Every patient included in the study was subjected to detailed history taking, complete general and dermatological examination and assessment of serum level of FST by using commercial ELISA kits.AV, non scarring and scarring patients had significantly higher frequency with positive family history, sun exposure and excess stress when compared to control group (p value  0.010, 0.005 and <0.001  respectively. However , No significant differences were found in risk factors between acne  groups. serum FST level was significantly lower in patients with acne  than control group although its level was significantly  lower in scarring acne patients than non scarring patients.