With almost all the ballots counted, he had received about 76% of the vote, the central election commission said.
The main opposition leader, Alexei Navalny, was barred from the race.
Addressing a rally in Moscow after the early results were declared, Mr Putin said voters had "recognised the achievements of the last few years".
Speaking to reporters, he laughed off a question about running again in another six years.
"What you are saying is a bit funny. Do you think that I will stay here until I'm 100 years old? No!" he said.