The bottleneck in current vector-based cancer therapy is the targeted and controlled release of therapeutics in tumors. Exosomes are submicron-sized vesicles that are secreted by all cell types and are involved in communication and transportation of materials between cells. Analogous in size and function to synthetic nanoparticles, exosomes offer many advantages, rendering them the most promising candidates for targeted drug or gene delivery vehicles. Patient-specific customized therapeutic strategies can be engineered using exosomes derived from the patient's own healthy cells. Therefore, exosome-based cancer therapy has the potential to become an important part of personalized medicine. Interest in exosomes as carrier organelles is relatively recent. Knowledge about exosomal biology and its applications remains limited. The present review is an attempt to describe the current status of the application of exosomes to cancer therapy and the potential challenges associated with their use.