Mormons and Christians do not worship the same Jesus—Mormonism presents Jesus as a created being and one of many gods, while the Bible declares Him as the eternal God. Because the identity of Christ is central to the gospel, this difference is not minor but foundational to the Christian faith.
Though Mormons use the same name as Christians for Jesus, the meaning they ascribe to "Jesus" is very different, and heretical, completely different from what the Bible teaches. Mormon doctrine teaches that Jesus is the spiritual offspring of "Father God" and "Mother God." In the Mormon view, Jesus is one of many gods, and human beings can even attain to "god" status. In short, Mormonism denies the unique divinity of Christ as God the Son. But the Bible teaches that the one God is revealed in the Trinity: God the Father, God the Son (Jesus), and God the Holy Spirit. Scripture shows that God is eternal, hence Jesus is (Psalm 90:2; Revelation 1:17; Colossians 3:16-17). The apostle John starts off his gospel by asserting that Jesus is God (John 1:1). The Mormon Jesus is not the true Jesus. Christians must never compromise on the truth about Christ. How one answers Jesus’ question, “Who do you say that I am?” is not secondary but decisive for salvation (Matthew 16:15).
"But they're so nice." And they look wholesome, too, in their white shirts and ties or modest dress. Likely, the polite Mormons that come to your door are nice. They're probably just passing along what they were brought up to believe. But the teachings of the Church of Latter Day Saints (Mormons) are not "nice"; in fact, they're spiritually harmful. They present Jesus differently from how He reveals Himself to us in Scripture. This isn't a "agree to disagree" issue. Believers must be sure we correctly answer one of the most meaningful questions Jesus asked: "But who do you say that I am?" (Matthew 16:15). The answer is God—a truth that Mormonism denies.
So what should you do if Mormons come to your door? You can use their evangelism effort to help bring them the truth. Instead of directly attacking their view, ask them if they would be willing to speak with you about Jesus—but using just the Bible, not the Book of Mormon. You can share Scriptures with them that offer the truth about Jesus. Don't expect spontaneous conversions, but plant a seed of truth. God will give the growth.