2008 Arizona Democratic presidential primary

One of the most diverse states in the nation with a heavily Latino population, Hillary Clinton was declared the winner of the Arizona Democratic Primary. According to exit polls, 68 percent of voters in the Arizona Democratic Primary were Caucasian and they opted for Clinton by a margin of 53–38. Clinton also won the Latino vote in Arizona by a margin of 55–41, which accounted for 18 percent of the electorate, as well as the Native American vote by a margin of 53-45 which accounted for 5 percent of the total voters in the primary. Obama carried the African American vote by a margin of 79–12, which accounted for 8 percent of the electorate. In terms of age, Obama won all voters under the age of 40 while Clinton won those over the age of 40. In terms of educational attainment, Clinton won all those who had a high school diploma, some college and/or college graduates while Obama won those who possessed postgraduate degrees. Clinton won self-identified Democratic voters and all ideological groups while Obama carried Independents in the state. Pertaining to religion, Clinton won all the major denominations in Arizona – Protestants backed Clinton 51–38, Catholics 57–37, Jews 51–44, and other Christians 47–46. Obama won nonreligious voters and voters who affiliated with other religions.

Clinton performed extremely well statewide in Arizona – carrying all counties but two: Coconino and Yavapai. She carried Maricopa County, which contains the state capital and largest city of Phoenix by a healthy margin as well as many of its suburbs. She also performed well in Southern Arizona, carrying Yuma and Tucson. She also carried seven of the state's eight congressional districts – the 5th District, which contains Tempe and Scottsdale, was won by Obama.

Former Governor Janet Napolitano endorsed Obama.

• 2008 Arizona Republican primary