This paper reports a Molecular Quantum Similarity study for a set of congeneric steroid molecules, using as basic similarity descriptors electron density ρ(r), shape function σ(r), the Fukui functions f+(r) and f−(r) and local softness s+(r) and s−(r). Correlations are investigated between similarity indices for each couple of descriptors used and compared to assess whether these different descriptors sample different information and to investigate what information is revealed by each descriptor.