There's not a lot known about Fortuna Mammosa save for Her name and the fact that She had a shrine or altar in the part of Rome called Region XII. This shrine was probably somewhere between the Porta Capena on the Caelian Hill (near the grove of the Camenae) and the Baths of Caracalla in the southern part of the city. The shrine was evidentally old enough or famed enough to be a landmark, as the street by which it was set up was called after it the Vicus Fortunae Mammiosae.

Mammosa, as one might guess, is just what it looks like: it is formed from the Latin root mamma, meaning "breast", with the suffix -ose, which adds the meaning of "abounding in", "full of", or "rich in". Given that, Fortuna Mammosa may either have been famous for having large breasts, or for having many breasts, either as animals do, or perhaps like the so-called Artemis (Diana) of Ephesus. If the former, perhaps Fortuna Mammosa was a Goddess of abundance and nourishment, Who brought good luck in mothering and nurturing, or Who helped the milk in a new mother's breasts to flow; or She may have been regarded as a Goddess Who cared for Her followers as a mother cares for her children.