Electron spectroscopy and argon ion etching were used to determine the depth and composition of the oxide layers of six competitive dental implant systems. To minimize problems associated with analyzing the active oxide layers, the implants were removed from their original packaging in an oxygen-free environment. The majority of the six implant systems were found to have similar oxide thicknesses in the range of 20 to 34 Å. Some variation was found in the extent of non-oxide surface contamination. Schlagwörter: dental implants, electron spectroscopy, oxide layer, titanium