Proton-sensitive afferent nerve fibers from the kidneys are putatively involved in renal inflammation by controlling sympathetic nerve activity and secretion of peptides (SP, CGRP). It is unknown which type of neurons in the dorsal root ganglion (DRG) projects to the kidney and responds to acid stimulation in two possible ways. Primary cultures of DRG neurons (T11-L2) retrogradely labeled from the kidneys were investigated by whole-cell patch-clamp measurements. Transient ASIC currents were identified by superfusion with pH6 solution and could be blocked by amiloride. Sustained TRPV1 currents were identified at pH5 and could be blocked by capsazepine. Neuronal cell sizes were classified by their capacitance. Small neurons (<80pF) showed no ASIC-currents and small TRPV1-currents. Medium-sized renal cells (80–160pF) had both ASIC and TRPV1 currents which were significantly greater than in non-renal neurons that actually showed no ASIC-currents. Large renal neurons (>160pF) showed large acid-induced currents of both types that were significantly greater than in non-renal neurons We conclude that predominantly large and medium-sized renal neurons are activated in a transient and sustained manner by stimuli that mimick tissue acidosis.