This invention relates to a method of photodynamic therapy (PDT) for bladder cancer and its use as an adjuvant or neoadjuvant therapy in the treatment of bladder cancer. The invention provides a composition comprising hexyl 5-ALA ester (HAL) or a pharmaceutically acceptable salt thereof for use in a method of photodynamic therapy for bladder cancer, wherein said composition is instilled into the bladder of a patient in need of such treatment and the inside of said bladder is exposed to blue light having a fluence rate of 1.5 to 12.5 mW/cm2
