This paper focuses on the first results of a micromorphological study on the Neolithic architecture from Mentesh Tepe (Azerbaijan), a settlement in the Southern Caucasus occupied during the first half of the 6th-millennium cal. BC. While earthen architecture has already been studied on a macroscopic scale, the use of micromorphology represents an original approach. This research highlights six different assemblages of Mentesh Tepe earthen material preparations, showing a diversity in the manufacturing processes (i.e. the way of preparing the earth, the building techniques, the way of using the earth during the construction) and in the care for the architecture. The well-prepared materials show intense mixing at a wet state with temper added to the composition, while less prepared elements are poorly mixed in a dry state with heterogeneous material. We have identified microscopic features of moulded mudbrick and a unique use of gypsum material for one specific building. From these results based upon the building techniques and material uses we discuss the possible function or status of the structures and the life-cycle of the buildings through time. These results question possible social differences within the Neolithic groups at a site scale. This corpus, while rather small, is the first in the area for Neolithic architecture, and our results only pretend to give a preliminary overview and some ongoing reflection on architectural questions about the first sedentary communities of the Southern Caucasus.