This paper aims at highlighting the process that leads to the setting up of a regular settlement pattern in inner Hadramawt. It points out the nature of the urban sites being seen in this context as small towns with a growth depending on irrigated agriculture. The religious function of these sites as well as their defensive function is also considered. Thus, we observe that the size and importance of towns in inner Hadramawt are rather limited, that they were cut off from the other South-Arabian regions until the end of the 1st cent. BC and that their development seems to have been conditioned by no other resources than agriculture.