Veterans gathered on Triumfalnaya Square in downtown Moscow along with Communist activists and youth groups carrying banners reading "Military reform is high treason," "The people and the army are one" and "We will save the army, we will save Russia."
Police estimated that more than a thousand people joined the rally.
"What is being done today under the guise of reform is the liquidation of the army, without which Russia has no future," Communist leader Gennadiy Zyuganov told the crowd.
The chief of the General Staff, Gen. Nikolai Makarov, said earlier this month that the reforms would be completed in next three or four years, and that they would make the military more compact, more mobile and better equipped.
The central point of the reform is the reorganization of the military command and control system and it includes a major cull of officer posts.
Defense Minister Anatoly Serdyukov said last year the Armed Forces would total 1 million servicemen, including 150,000 officers by 2012.
Russia has already downsized its Armed Forces from 4.5 million in the Soviet era to about 1.2 million personnel, including 310,000 commissioned officers, at present.
In addition, each of Russia's six military districts will have an airborne brigade as a rapid-reaction unit. These units will be used to accomplish tactical missions "promptly and effectively."
