Oregon moved into the No. 1 spot in both major polls, which were released Sunday.
The Ducks moved up from the No. 2 spot in the AP media poll and USA Today coaches poll after their rout of California on Saturday.
Alabama, which was No. 1 for 10 weeks, fell to No. 4 in the AP poll and No. 5 in the coaches poll after falling 29-24 to Texas A&M in Tuscaloosa.
Oregon (10-0) received 44 of 59 first-place votes in the coaches poll and 45 of 60 votes by the AP. Kansas State, also undefeated, moved up to No. 2 and received 14 first-place votes in both polls. Notre Dame, the third of three undefeated teams, received the other remaining first place vote and moved up to the No. 3 spot in both polls.
It is the first time the Fighting have received a No. 1 vote since September of 2006.
Georgia took over the No. 4 spot in the coaches poll after clinching a spot in the SEC title game after shutting out Auburn 38-0.
Alabama fell to its lowest ranking in the coaches poll since the end of 2010. Alabama is still likely to meet Georgia in the conference championship game in Atlanta.
No. 6 Florida State and No. 7 Florida remained in their same spots while LSU leapfrogged Clemson for No. 8 after topping then-No. 23 Mississippi State in the coaches poll. Ohio State is No. 6 by the AP but is ineligible to be ranked in the coaches poll.
Texas A&M rounded out the top 10 in the coaches poll but moved up to No. 9 by the AP after its huge win over Alabama.
The Aggies moved ahead of No. 11 South Carolina and No. 12 Oklahoma.
Stanford, No. 13 in the coaches poll and No. 14 by the AP, visits Oregon this week in a Pac-12 clash.
No. 25 Kent State is ranked by the AP for the first time since November of 1973.