Some 20 million people were eligible to vote for a replacement for outgoing President Alan Garcia in a race pollsters said was within 4 percentage points, The Financial Times said.
Leftist former army officer Ollanta Humala had a narrow poll lead over Congresswoman Keiko Fujimori, daughter of the imprisoned former leader Alberto Fujimori, the report said.
The elder Fujimori is serving a 25-year prison sentence for human rights abuse convictions, some of which relate to the forced sterilization of more than 250,000 women between 1993 and 1999.
However, Humala also has a questionable rights history dating back to 2000 when he led a military rebellion against Fujimori, the newspaper said.
Curiously, both candidates had similar economic campaign platforms. The country has one of the world's fastest-growing economies, rooted largely in its mining sector. Both candidates said by increasing taxes on mining, social benefits for students and seniors would be bolstered, the report said.
Election results were expected to be released early Monday, officials said.