The Second International Conference on Synthetic Biology (SB2.0) took place on May 20-22, 2006, at the University of California, Berkeley. The conference brought together a diverse group of participants from a variety of disciplines, including some of the world’s leaders in biological engineering, biochemistry, quantitative biology, biophysics, molecular and cellular biology, bioethics, policy and governance, and the biotech industry. A collaborative effort of Berkeley Lab, MIT, UC Berkeley, and UCSF, the conference sought to promote and guide the further, constructive development of the field.