Abstract: A prefabricated building structure, comprising: —a first and a second pillar (21, 22) reciprocally stacked and having a preponderant longitudinal extension direction (20); an upper end (211) of the first pillar (21) being located at a lower end (221) of the second pillar (22); —a beam (3) extending substantially horizontally and having a first end (31) located at said upper end (211) and said lower end (221); —reciprocal fixing means (9) for reciprocally fixing the first pillar (21), the second pillar (22) and the beam (3); said reciprocal fixing means (9) being able to be at least partly incorporated in the first pillar (21), in the second pillar (22), in the beam (3). The reciprocal fixing means (9) comprises projecting means (91) and corresponding housing means (92) in which the projecting means (91) fits defining a joint.