Winner Donald Trump Primary date May 17, 2016 Poll source Date 1st 2nd 3rd Other Primary results May 17, 2016 Donald Trump 64.51% Ted Cruz 16.50% John Kasich 15.83% DHM Research/Oregon Public Broadcasting/Fox 12[1] Margin of error: ± 5.7% Sample size: 324
May 6–9, 2016 Donald Trump 45% Ted Cruz 14% John Kasich 14% Undecided 19%, Wouldn't Vote 7% Hoffman Research[2] Margin of error: ± 4.16% Sample size: 555
April 26–27, 2016 Donald Trump 43% Ted Cruz 26% John Kasich 17% Undecided 13% DHM Research Margin of error: ± 7.7% Sample size: 169
July 22–27, 2015 Donald Trump 18% Scott Walker 12% Jeb Bush 11% Ted Cruz 10%, Ben Carson 9%, Rand Paul 6%, Mike Huckabee 6%, John Kasich 4%, Marco Rubio 3%, Chris Christie 2%, Carly Fiorina 2%, Rick Santorum 2%, Bobby Jindal 1%, Rick Perry 1%, Lindsey Graham 0%, Jim Gilmore 0%, George Pataki 0%, Other 2%, DK 12% Public Policy Polling Margin of error: ± 5.1% Sample size: 375
May 22–27, 2014 Mike Huckabee 21% Ted Cruz 16% Jeb Bush 15% Rand Paul 15%, Chris Christie 12%, Marco Rubio 4%, Paul Ryan 3%, Scott Walker 3%, Rick Santorum 2%, Someone else/Not sure 10%