Mr Putin, who has run the country since 1999 as either president or prime minister, is standing for another six-year term.
Seven other candidates are standing, including a millionaire communist and a former reality television host.
Russia's main opposition figure, Alexei Navalny, is prohibited from standing.
Opinion polls give Mr Putin about 70 percent support, nearly 10 times the backing of his nearest challenger.
On Russia's eastern edge, in the Pacific coast city of Petropavlovsk-Kamchatsky, polling stations have opened.