The new terminal is Southeast Asia's first dedicated no-frills terminal, and will rival a similar one at Singapore's Changi airport due to open on Sunday.
Built at a cost of 108 million ringgit (29.2 million dollars), Malaysia's terminal will be officially opened by Prime Minister Abdullah Ahmad Badawi later Thursday.
Work on the facility located some 20 kilometres (12 miles) from the futuristic Kuala Lumpur International Airport (KLIA) took a record nine months to complete. It will initially handle 10 million passengers a year.
The Malaysia-based budget airline AirAsia is currently the only carrier that has confirmed it will use the new building.
The airline, which dominates the crowded Southeast Asian low-cost sector, wants to ride the travel boom not only in its home region of half-a-billion people, but also in the emerging China and India markets.
AirAsia's success has sparked a slew of other low-cost airlines, notably in neighbouring Singapore.