Background: Acne vulgaris is one of the most common skin diseases all over the world. The aim of this study was to measure serum levels of Thymosin β4  in patients with acne vulgaris indicating its potential role as a novel biomarker in diagnosis of acne. Methods: This study included 20 patients with moderate acne vulgaris according to Global Acne Grading System  (GAGS), presented to the Dermatology Department, Benha University Hospital,  out patients clinics, in addition to 20 apparent healthy controls.  All studied patients were subjected to history taking, dermatological examination and measurement of serum Thymosin β4. Results: the mean serum levels of Thymosin β4 was higher in control group with insignificant difference than patients group, there was insignificant correlation between serum Thymosin β4 level and age, sex, duration, onset and smoking history in AV patients. Conclusion:;  serum Thymosin β4 levels are higher in control group compared to  AV patients, and  it seems to have an essential role in the etiopathogenesis of  this inflammatory skin disease, So it is considered to be a promising target in treating inflammatory diseases.