Recent advances in stretchable electronics have seen the emergence of new technologies, and intensive efforts are being dedicated to embed some form of “intelligence” in various types of surfaces. However, the primary challenge in the field of stretchable electronics has been the development of stretchable or elastic electrical wiring that is both highly conductive and highly stretchable. Another challenge has been the development of manufacturing processes for integrating active device components as non-stretchable regions with electrical wiring as stretchable regions; the rigid/stretchable interfaces of these components require both high conductivity and high mechanical stability. In this article, we review the fabrication of carbon-nanotube-based elastic conductors with high electrical conductivity and mechanical stretchability as a representative example of stretchable organic integrated circuit electronics. Furthermore, we demonstrate the development of rubber-like stretchable integrated circuits for large-area human/machine interfaces. The fabrication process described in this article exploits the advantages of integrating a variety of electrical functional materials, ranging from rigid and semi-rigid elastomers to gels, with electronic circuits. The stretchable devices can be spread over a wide range of surfaces, including free surface curvatures and movable parts, thereby significantly increasing the scope of application of stretchable electrical and electronic circuits.