Voltage-gated potassium (Kv) channels serve a wide range of functions in both excitable and non-excitable cells. In neurons these include the regulation of the resting membrane potential and control of the shape, duration and frequency of action potentials. The large number of Kv subunits presents a challenge to determine the molecular composition of the native currents. We attempted to identify the Kv subunits underlying the delayed rectifier current (I_K) in cultured small mouse dorsal root ganglia (DRG) neurons. Using extracellular Stromatoxin (ScTx) and intracellular Kv2.1 antibodies we recently reported that approximately 60% of the I_K current in these DRG neurons is carried by both homotetrameric Kv2.1 and heterotetrameric Kv2.1/silent Kv channel complexes. The 40% of I_K remaining after ScTx (100 nM) pretreatment, was reduced with 1 mM extracellular TEA (n = 6) indicating that this part of the I_K current could be represented by the Kv subunits Kv1.1, Kv3.1, Kv3.2 and/or Kv3.3, and possibly a fraction of KCNQ2 and KCNQ2/3 channels, which underlie the M-current in small DRG neurons. Using channel specific toxins we determined the contribution of each channel to the remaining 40% of I_K. Furthermore, we detected the presence of Kv3.1, Kv3.2 and Kv3.3 mRNA using RT-PCR in freshly isolated DRG. These observations support a substantial role of at least the Kv3.x subunits in small DRG neurons which are visceral and somatic sensory neurons that conduct information about temperature, pressure and touch.