Abstract: A seat for a cabin of a vehicle, presenting breathable seating and backrest portions (7, 8). The seat (1) has a shell (11), which is rigidly coupled to the rear side (4al) of the backrest (4) and presents an air intake (15) and air vents (12a-12d) for the cabin, and an air-conditioning unit (16), which is housed in the shell (11) and has a coolant inlet (21), an expansion valve (22) connected to the coolant inlet (21), an evaporator (23) connected to the expansion valve (22) for cooling the air sucked in, a coolant outlet (24) connected to the expansion valve (22) and an electric fan (25). In the shell (11) and in the base (2) of the seat (1) there are air distribution chambers (18, 32) communicating with the outlet (19) of the air-conditioning unit (16), the air vents (12a-12d) and the breathable seating and backrest part portions (7, 8).