Methyl aminolaevulinate photodynamic therapy (MAL-PDT) is an effective treatment for Bowen's disease (BD) of the lower extremities. Er:YAG ablative fractional laser (AFL) treatment removes the stratum corneum to increase MAL uptake and may improve efficacy. However, no studies have directly compared the efficacy of MAL-PDT with and without Er:YAG AFL in treating BD of the lower extremities in Asians.