The protein transduction system has been employed for delivery of bioactive proteins into cells via an endocytotic mechanism. However, trapping of endocytosed proteins in the endosome may significantly attenuate biological actions in cells. The present investigation demonstrated that endosomal release of transduced protein could be artificially accelerated by exposure to fluorescent light. Exposure to light at 480 nm stimulated endosomal release of transduced FITC-11 arginine-protein transduction domain (11R-PTD), TAT-PTD and Antennapedia-PTD. Moreover, FITC-11R-p53 protein was released from endosomes following stimulation with light. These data suggest that photo-acceleration is a more efficient strategy in terms of the protein transduction system.