According to NBC News/Wall Street Journal/Marist Poll released today, Trump leads Senator Ted Cruz of Texas with seven points in Iowa.
This is quite a big jump as three weeks ago, Trump, 69, trailed Cruz by four points in this crucial state.
The poll comes days ahead of the first presidential vote is caste in the Iowa Caucus on Monday, which will formally kick off the process to elect the new US president in November.
The second and last four-year term of the US President Barack Obama ends on January 20, 2017.
As per the latest poll, Trump has support of 32 per cent among likely Republican caucus goers.
He is followed by Cruz with 25 per cent and Marco Rubio at 18 per cent.
The polls also show that Trump has a massive 19 point lead over Cruz in New Hampshire while in South Carolina his lead is 16 points.
"Trump is positioned to run the house in these first three states," said Lee Miringoff, director of the Marist College Institute for Public Opinion.
"Will it happen? The answer depends on when or if anti-Trump sentiment will coalesce to interrupt his march to the nomination," he said.
According to a Monmouth University Poll releasedon Thursday, Clinton, 68, leads Sanders in Iowa by just five percentage points.
This is a big slump in her popularity given that in December her lead over Sanders was a whopping 22 points.
"Support for Sanders has come from those who are new to the process, but the current poll indicates he is also cutting into Clinton's lead among die-hard Democratic partisans," said Monmouth polling director Patrick Murray.