He wasn't a believing Christian, though he was a deist.
http://en.wikipedia.org/wiki/Thomas_jefferson#Religious_viewsJefferson used deist terminology in repeatedly stating his belief in a creator, and in the United States Declaration of Independence used the terms "Creator" and "Nature's God". Jefferson believed, furthermore, it was this Creator that endowed humanity with a number of inalienable rights, such as "life, liberty, and the pursuit of happiness". His experience in France just before the French Revolution made him deeply suspicious of Catholic priests and bishops as a force for reaction and ignorance. Similarly, his experience in America with inter-denominational intolerance served to reinforce this skeptical view of religion. In a letter to Willam Short, Jefferson wrote: "the serious enemies are the priests of the different religious sects, to whose spells on the human mind its improvement is ominous."<34>
Jefferson was raised in the Church of England, at a time when it was the established church in Virginia and only denomination funded by Virginia tax money. Before the Revolution, Jefferson was a vestryman in his local church, a lay position that was part of political office at the time. He also had friends who were clergy, and he supported some churches financially. During his Presidency, Jefferson attended the weekly church services held in the House of Representatives. Jefferson later expressed general agreement with his friend Joseph Priestley's Unitarianism, that is the rejection of the doctrine of Trinity. In a letter to a pioneer in Ohio he wrote, "I rejoice that in this blessed country of free inquiry and belief, which has surrendered its conscience to neither kings or priests, the genuine doctrine of only one God is reviving, and I trust that there is not a young man now living in the United States who will not die a Unitarian."<35>
Jefferson did not believe in the divinity of Jesus, but he had high esteem for Jesus' moral teachings, which he viewed as the "principles of a pure deism, and juster notions of the attributes of God, to reform
moral doctrines to the standard of reason, justice & philanthropy, and to inculcate the belief of a future state."<36> Jefferson did not believe in miracles. He made his own condensed version of the Gospels, omitting Jesus' virgin birth, miracles, divinity, and resurrection, primarily leaving only Jesus' moral philosophy, of which he approved. This compilation was published after his death and became known as the Jefferson Bible.