This master’s thesis deal with design of EV-55 Outback airplane with pressurized cabin. In this thesis are given common principles and requirements of regulations on construction pressurized cabin. A necessary fuselage modifications and fuselage construction are included. Also construction and build up of air-conditioning system and emergency oxygen system are included. Some parts of this thesis are about weight and balance, definition of pressurized cabin load, simple stability analysis and basic flight performance calculation. At the end of this master’s thesis a result of weight and flight performances are compared with analogous airplanes by other producers.