The intestinal bacterial ecosystem has gained increasing interest from the scientific community because of its demonstrated involvement in the aetiology and/or outcome of different physiopathological conditions, especially inflammatory diseases. The gut microbiota is affected by the aging process in terms of composition and functionality (Tiihonen et al., 2010). In a sort of self-sustaining loop, the aged-type microbiota has been hypothesized to contribute to several age-associated phenomena such as immunosenescence and inflammaging ( Guigoz et al., 2008). The impact of the aging process on the gut microbiota has been addressed in several studies, some of which used modern molecular characterization techniques; these studies have been thoroughly and carefully reviewed by Tiihonen et al.(2010). However, an important contribution to the understanding of several aspects of this phenomenon has been provided by the two most recent studies in the field (Biagi et al., 2010; Claesson et al., 2010). These studies were performed with two different very up-to-date molecular techniques, the Human Intestinal Tract Chip (HIT Chip, a phylogenetic DNA microarray) and the pyrosequencing, which yielded fairly comparable ( Claesson et al., 2009; Van den Bogert et al., 2011). The results described in the studies are quite unexpected and, taken together, can shed some light on very important question in the field.