The figures were the latest indication that Russia was sliding toward recession -- and potentially a deep one should oil prices remain low -- presenting a major challenge to Putin amid his current showdown with the West.
The economy ministry said gross domestic product for the month contracted by 0.5 percent year-on-year for the first time since October 2009.
The ministry chalked up the negative growth to a slowdown in sectors including services, agriculture, extraction of mineral resources and construction.
Under pressure from the low oil price and Western sanctions over the Kremlin's support for separatists in Ukraine, Russia is heading for a sharp recession complete with the collapse of the ruble and double-digit inflation.
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"This is the beginning of a recession," Ruslan Grinberg, director of the Institute of Economics at the Russian Academy of Sciences, told AFP.
Putin's pact with voters has for years been based on relative prosperity and high oil prices.
But many economists said such statements exposed a lack of a firm plan to deal with the crisis.
The ruble has fallen some 40 per cent against the dollar this year.
Today, the ruble was down by around 6 percent against the greenback at the opening but later recovered some of the losses and traded at around 56 rubles to the dollar in afternoon trading.
Russia's national currency fluctuated wildly earlier this month, forcing Russians to snap up imported goods ahead of expected price hikes.