The characterization of 13.56 MHz low pressure inductively coupled plasmas used for diamond deposition has been performed with a Langmuir probe. The plasma potential (V-p), electron temperature (T-e), electron density (N-e), ion density (N-i), and electron energy distribution function (EEDF) were measured in a CH4/H-2 plasma with 10-50 mTorr of the gas pressure at 1 kW of the plasma power, and were compared with those of an Ar plasma. We found that the V-p, N-e, and N-i have a similar radial distribution, which has a peak at the center axis and decreases outward in the radial direction, while the T-e is almost constant within the radius of 20 mm and slightly decreases toward the chamber wall. It was also found that with increasing pressure the V-p and the T-e decrease, whereas the N-e increases, except for a CH4/H-2 plasma at 50 mTorr. The transition from a Maxwellian distribution to a Druyveysten distribution was observed at 10 mTorr in the EEDFs of Ar plasmas, while it occurred at 20 mTorr in CH4/H-2 plasmas. The EEDF of a CH4/H-2 plasma at 50 mTorr has a hump at similar to 6 eV corresponding to the resonant peak of the vibrational excitation cross section of CH4 molecule.