Ireland's win over Scotland at the weekend and England's loss to France, means the two teams swap position on the rankings table.
It's the first time Ireland have been number two since August 2015.
Ireland are now on 87.85 points - over six behind the world's number one team New Zealand, and 0.35 in front of England, who they face at Twickenham this weekend as they go in pursuit of only their third Grand Slam.
Australia are at four followed by South Africa, Scotland and Wales.
All Blacks coach Steve Hansen isn't at all surprised by the results in the Six Nations Championship and Ireland's success.
Hansen says Ireland have pushed them very close over the last few years and he expects that to continue.
Ireland beat the All Blacks in Chicago in 2016.
France have jumped up two spots to eight with Argentina and Fiji dropping to nine and ten.
France tour here in June and Hansen says the tricolours are getting into form.
"France are a side that we all know, can either turn up of turn off and when they turn up they're extremely difficult to play."
"They're big, they're athletic and they're skilful and they've got a number of people out (injured) so they're only going to get better."
Tonga is ranked 13th and Samoa 16th.