The nanoscratching-induced deformation of monocrystalline Si has been investigated using transmission electron microscopy (TEM). The results indicate that amorphization and formation of crystalline defects are two dominant phenomena associated with the scratching processes. TEM analyses reveal that amorphization occurs at extremely small scratching loads. Stacking faults and twins are nucleated at a smaller load than that for dislocation. Dislocations start to nucleate along Si {111} planes when the normal scratching load is greater than a threshold value and penetrate deeper into the Si subsurface with the increasing load. Both normal load and tip radius have significant influence on the deformation, which are somehow different from those associated with nanoindentation and nanogrinding.