With the Michigan State loss to North Carolina and Arizona's win over UNLV, the Wildcats have officially moved to the top spot in the country.
Arizona received 30 of 32 first-place votes in the coaches' poll, with Ohio State and Syracuse receiving one each.
In the AP poll, Arizona is the first AP No. 1 team from the Pac-12 since 2006 and this is the 30th week in its history that Arizona has been the AP No. 1.
The Wildcats were last ranked No. 1 in both the AP and USA Today polls on March 10, 2003 and actually held the top spot for 13 weeks that season.
"I think it reflects the quality of our program, the incredible atmosphere that we have in McKale, the great teams and players of the past, and certainly this year's team," Arizona head coach Sean Miller said.
"To be ranked No. 1 is maybe the greatest compliment that you can have."
Arizona will now look to defend its number one ranking starting Wednesday with a home game against New Mexico State.