With 99 percent of precincts in, TedCruz led with 28 percent of the vote versus 24 percent for Trump and 23 percent for Rubio.
The caucus was the first fight in a bitter conflict in the Republican Party over rival ideologies.
Cruz ran on a pledge to faithfully represent the grassroots right, who he argued would respond by turning out in greater numbers in the general election. Rubio, solidly conservative himself, argued he could bring voters who had backed Democrats in the past into the GOP field with a more universal message that emphasized his son-of-immigrants biography.
Trump took a completely different path, ignoring GOP tradition in favor of a swaggering populist appeal that targeted independents and loose partisans who are disillusioned with politics entirely.