Objective : Photodynamic therapy (PDT) using topical aminolevulinic acid (ALA) has increasingly been used for the treatment of acne vulgaris and several studies have shown its clinical efficacy. However, ALA-PDT needs a relatively long incubation period and is frequently associated with adverse effects. Triptophan and Riboflavin has been introduced as a new photosensitizer for the treatment of acne recently. Method : 11 patients with acne vulgaris were received PDT with tryptophan and riboflavin four to six times over two to three months. The photos of each patient were taken before and after treatment. Result and conclusion : PDT with tryptophan and riboflavin may be an effective and safe treatment for the Acne vulgaris patients.