The vibro-indentation with a spherical indenter on low and medium carbon steels was performed in ultrasonic (20 kHz) and in low frequency (50 Hz) ranges in order to establish the foundation for the vibro-Brinell hardness testing that was suggested in our first report. Experimental results show that Meyer's law is still valid in case of the vibro-indentation, provided that Meyer coefficient and index are taken to be the functions of the amplituae and frequency. It is also shown that the vibro-indentation law and the vibro-Brinell hardness can be reduced to Meyer's law and Brinell hardness respectively, under the load superposition hypothesis.