It will cost Malaysia US$25 million (S$37 million), which the government has said will be offset as part of a US$900 million defence deal struck with Moscow in 2003.
Malaysia's first astronaut will spend 10 days in space.
The spacecraft blasts off from Baikonur Cosmodrome in Kazakhstan at 9.20pm Malaysian time tonight.
Two other astronauts will travel with Dr Sheikh Muszaphar Shukor: Russian Yuri Malenchenko and American Peggy Whitson.
The approved flight menu includes chicken biryani, satay ayam and banana rolls.
The mission coincides with the last days of Ramadan. Malaysian clerics have excused Dr Muszaphar from fasting while in space, but he has said he will try to fast.
Dr Muszaphar will return to Earth on Oct 21 with two Russian members of the space station crew.
Astronauts Whitson and Malenchenko will stay on as the station's new crew.