Here we report the experimental observation of circular dichroism induced by optical extrinsic chirality in the second harmonic field (800nm-400nm) of self-organized nanowires arrays with sub-wavelength periodicity (160nm). In the measurements, the second harmonic signal generated by the curved nanowires was recorded as a function of the incidence angle for left-and right-handed impinging pump fundamental light; the results show more than 50% of visibility of the extrinsic optical nonlinear circular dichroism.