In this work, flexible multifunctionalized carbon nanotube (CNT)-based hybrid nanowires are synthesized through surface modification processes. The good dispersability of the hybrid nanowire in polar solvents facilitates directly making fine patterns with a minimum width of 40 m for applications of flexible and stretchable circuits (FSCs). The hybrid nanowire possesses a flexible and highly conductive structure which demonstrates stable electro-mechanical properties on polydimethylsiloxane (PDMS) substrates under large structural deformation. FSCs fabricated from the hybrid nanowires show a constant resistance of 0.096 (-1) (equivalent of a resistivity 0.96 m) under repeated bending cycles. The FSCs also have a low and stable sheet resistance of 0.4 (-1) for strains up to 30%, which is almost four orders of magnitude lower than that of pure CNT samples (1316 (-1)). Further improved stretchability and electro-mechanical properties (0.1 (-1), at the strain of 100%) are achieved with a prestrain PDMS substrate. Repeated deformation tests demonstrate the high reliability of FSCs. The observed stable and reliable electro-mechanical performance of FSCs suggests the potential use of the material in wearable and portable electronics.