"Tuesday, you can end Mitt Romney's hypocrisy on religious freedom."
But Mr Romney's decision eight years ago did not appear to have damaged him in the state, where 3.4 per cent of the population is Jewish.
Mr Gingrich, who beat Mr Romney in last month's South Carolina primary, came second with 32 per cent of the vote. The conservative Christian candidate Rick Santorum walked away wuith 13 per cent, while Ron Paul, whose attacks on aid to Israel have made him unpopular with Jewish groups, took only seven per cent.
The race now moves to Nevada, the home state of Mr Gingrich's biggest financial backer, Jewish casino mogul Sheldon Adelson.