A new method for hardness–depth profiling on the nanometer scale has been developed. In this method, the hardness–depth profile was obtained by a stepwise removal of a surface layer by ion sputtering and measurement of the hardness by nanoindentation at each step using the same maximum load (250 μN). During removal of each surface layer the composition was obtained using Auger electron spectroscopy. For comparison, the hardness–depth profile was also assessed by a stepwise increase of the maximum load applied to the original surface. The sample used in these experiments was a Ti–6Al–4V cast alloy, doubly implanted with carbon (120 kV/3 · 1017 cm−2 and 60 kV/4 · 1017 cm−2). The hardness–depth profiles were related to the composition–depth profile. It followed that only the constant load and removal method provides a direct relation between hardness and composition at a given depth.