With a tuxedo, wedding band and permission from Texas state authorities to wed his Russian-American girlfriend, Malenchenko was fully prepared to become the first person to marry from space.
But he renounced the idea following a conversation with his superiors, a Russian space agency Rosaviakosmos spokesman said.
"There will not be a marriage in space. We talked with him and he came to the conclusion that it is better not to do it," Sergei Gorbunov told the daily Izvestia.
Malenchenko, 41, is a colonel in the Russian armed forces and must have approval to marry his fiance, Yekaterina Dimitrieva, who emigrated to the United States from Russia when she was four years old, Gorbunov said.
"He knows certain secrets. To change his family situation, he must first make a declaration to his superiors," Gorbunov said.
Dmitrieva, 26, currently lives in Houston, Texas.
Malenchenko, who divorced several months ago, proposed to Dmitrieva in December before blasting off for the ISS in April along with US astronaut Eduard Lu.
Now he will have to wait until he returns to Earth in autumn to wed his bride and follow through on plans for a honeymoon in Australia.
"There is a code of behavior for cosmonauts in orbit which regulates their life and work. You do not find terms like 'marriage' in it," Gorbunov said.
"There are also liaison problems," he said. "This is not a private boutique, but a state organization. We cannot allow the use in this manner of state communications channels and the Americans can't either."
Malenchenko had planned to go through with the interplanetary wedding after receiving the wedding band and tuxedo aboard a Progress cargo vessel that refueled the ISS in June.