The successful application of gene therapy through DNA transfection into the cell is still a great challenge in ongoing research. Hyperbranched polyamines are highly branched macromolecules, and have gained significant attention in the last two decades, due to their relative ease of preparation, their shape, and their multi-functionality. This review deals with the syntheses of various hyperbranched polyamines that are prepared through a one-step polymerization process. Furthermore, we present the current status of polyamines as gene carriers and describe their versatility, and their properties such as structure-property dependency, gene transfection efficiency, and cytotoxicity profiles of hyperbranched polyamines.