An individual carbon nanocoil was clamped between two AFM cantilevers and loaded in tension to a maximum relative elongation of similar to42%. The deformation of the nanocoil agrees well with an analytical model of the spring constant that accounts for the geometric nonlinearity. The nanocoil behaves like an elastic spring with a spring constant K of 0.12 N/m in the low strain region. No plastic deformation was detected. High-resolution microscopy images and the electron energy loss spectrum (EELS) indicate that the nanocolls are amorphous with a sp(2)/sp(3) bonded-carbon ratio of similar to4:1.