There is currently much excitement surrounding the rapidly growing discipline of synthetic biology, which utilizes the design and construction principles of engineering to develop, evolve and standardize biological components and systems. This systematic approach to improving and increasing the programmability and robustness of biological components is expected to lead to the facile assembly of artificial biological components and integrated systems that enable innovative approaches to solving a wide range of societal challenges. Here we discuss the current state of the art and outline the next wave of synthetic biology: integrating individual components into systems.