Endosymbiosis can be considered a regressive or degenerative evolutionary process characterized at the genomic level by genome erosion and degeneration due to high mutational pressure towards AT. The genomic and biological complexity of endosymbionts must be less than that of the free-living bacteria from which they evolved. In the present work, we contrasted whether two proposed metrics for measuring genomic complexity in both types of bacteria, Genomic Signature (GS) and Biobit (BB), reflect their complexity, expecting higher values in free-living bacteria than in endosymbionts. On the other hand, we have tried to delve into the factors that contribute to the reduction of metric values in endosymbionts, as well as their eventual relationship with six genomic parameters associated with functionality.