Trump, a billionaire businessman, draws the support of 30 percent of Republican primary voters, while Cruz, a U.S. senator from Texas, draws at 27 percent. Ohio Gov. John Kasich has risen to 22 percent in the survey, while Florida U.S. Sen. Marco Rubio receives 20 percent.
The survey reflects a slight gain from last month for Trump, who in the February survey trailed Cruz by a 28 percent to 26 percent margin. Trump subsequently scored significant victories in South Carolina, Nevada and in several Southern states on Super Tuesday.