Question: Do Some Latter-day Saints Practice Polygamy?
Do some members of The Church of Jesus Christ of Latter-day Saints practice polygamy?
NO. Members of the LDS Church do not practice polygamy. Any member of The Church of Jesus Christ of Latter-day Saints found practicing polygamy or being affiliated with a polygamist group is excommunicated from the Church. Polygamist groups are not affiliated with the LDS Church in any way, shape or form.
Elder Quentin L. Cook of the Quorum of the Twelve Apostles
The Church of Jesus Christ of Latter-day Saints officially discontinued the practice of polygamy in 1890: 118 years ago. It's a significant part of our distant past, not of our present" ("Church Seeks to Address Public Confusion Over Texas Polygamy Group").
See Polygamy: Not Practiced in the LDS Church
and Polygamy: Official Statement
to learn more.