A Zenit-M rocket with a military satellite was launched from the Baikonur space center that Russia rents in Kazakhstan at 2 p.m. Moscow time (noon GMT).
"The separation of the spacecraft occurred successfully and on schedule," a spokesman for the Federal Space Agency said.
"A Cosmos-series satellite will expand the orbital group of Russia's military satellites," he said.
The satellite launch had been originally scheduled for December 2006, but was postponed until June for technical reasons.
Russia is reportedly operating a network of about 60-70 military reconnaissance satellites.
Zenit-M is a modified version of the Zenit-3SL delivery vehicle used to launch spacecraft from the Sea Launch consortium's floating launch platform in the Pacific Ocean.
The modernized Zenit rocket has only two stages, while the Zenit-3SL uses an additional booster.