Aim and Methods: Microneurographic techniques were used to study the innervation territories of single unmyelinated C mechano-nociceptors (CM) and C mechano-heat nociceptors (CMH) in the skin of the leg and foot in healthy volunteers.Results: The locations and sizes of the mechano-receptive fields (mRFs) of 77 C units were determined. Most units recorded in the peroneal nerve at knee level had their mRFs on the foot (60 units), fewer on the leg (14 units) and toes (3 units). The mean areas were largest on the leg (198 sq mm), smaller on the foot (88 sq mm) and toes (35 sq mm). The mean maximal diameters of mRFs on the leg (22.3 mm) and foot (15.3 mm) were of similar size as the radius of axon reflex flares evoked by noxious mechanical stimuli in these regions. A rough estimate indicates that the innervation density would be approximately 65 CM and CMH units/sq cm on the leg and 260 units/sq cm on the foot.Conclusions: The overlapping nociceptor innervation in the skin allows for spatial summation in response to punctate noxious stimuli, a prerequisite for good accuracy in localizing painful events from a C-fiber input. The reduction in size of the innervation territories distally allows for finer discrimination of spatial dimensions of noxious stimuli distally in the extremities as compared to central regions of the body.