From the Missouri Republican Party:
While major media outlets have not yet called Missouri’s election, it seems clear that Donald Trump narrowly won the state; however, he did not reach the 50% threshold required to make Missouri a winner-take-all state. This means that Missouri will allocate 12 delegates to the statewide winner (Trump) and our remaining 40 delegates to the top vote-getter in each congressional district.
Since the votes were so close, these numbers are tentative pending Secretary of State certification of the vote:
Donald Trump: 37 delegates (12 for the statewide win, 5 each for winning Congressional Districts 1, 2, 3, 6, and 8)
Ted Cruz: 15 delegates (5 each for winning Congressional Districts 4, 5, and 7)