Granuloma annulare is a benign, self-limiting dermatosis of unknown cause, and is characterized by erythematous annular papules and plaques commonly located on the distal or dorsal extremities. Many topical and systemic treatments including topical and intralesional corticosteroids, topical calcineurin inhibitors, cryotherapy and psoralen plus ultraviolet A (PUVA) have been tried for granuloma annulare, but the results were variable. Recently, there were few reports for treatment of granuloma annulare with topical 5-aminolaevulinic acid (ALA) photodynamic therapy (PDT). Herein, we present a case of granuloma annulare successfully treated with PDT using 5- ALA with low light dose (10~14 J/cm2) in a 3-year-old boy.