Gene therapy has drawn significant attention as a potential method for treating both acute illnesses and chronic diseases. Current research efforts have focused on developing carriers that effectively compact and protect naked DNA, RNA and siRNA, which are rapidly degraded by enzymes in the blood. As an alternative to viral and polymeric carriers, nano-particles have been introduced as promising carriers with low toxicity profiles and well-controlled gene delivery efficiency. While significant advances have been made for in vitro applications, much still remains to be done, especially for in vivo translation. Here we provide a concise review on the development of nano-particles for gene delivery.