For as long as Mormonism has existed, people have questioned whether the faith is Christian. Of course, members of The Church of Jesus Christ of Latter-day Saints are quick to point detractors to their first Article of Faith, which says, "We believe in God, the Eternal Father, and in His Son, Jesus Christ, and in the Holy Ghost." In addition, the Church recently addressed the issue in their Gospel Topics Essays on LDS.org.
"Members of The Church of Jesus Christ of Latter-day Saints unequivocally affirm themselves to be Christians," the Church's essay states. "They worship God the Eternal Father in the name of Jesus Christ."
Interestingly, though the Christianity of Mormons has been called into question for nearly two centuries, a Pew survey shows members of the Church score highest of all religions on knowledge about Christianity.* On 12 questions about the world's largest faith, including many questions about the Bible, Mormons answered an average of 7.9 correctly. White evangelical Protestants (7.3 correct on average) were second.
Mormons weren't quite at the top when it came to general religious knowledge, though. Perhaps surprisingly, that honor went to the atheists and agnostics who were surveyed. Jews were next, and Mormons came in a close third. Atheists and agnostics were also the most knowledgeable about the role of religion in public life, including questions about the U.S. Constitution and public school systems.
Other surveys have established that Mormons, in general, are exceptionally well-educated. But even after controlling for differing levels of education, the survey showed that Mormons maintain their bronze medal in religious knowledge (again, behind atheists/agnostics and Jews).
Mormons also scored highly in scripture reading scores. Latter-day Saints, black Protestants, and white evangelicals read religious materials most frequently. However, although more than half of Mormons surveyed reported reading materials to learn about their own religion at least once a week, only a small fraction reported frequent learning about other religions.
*Though from 2010, this study is the most in-depth and recent on this subject.