Mormon garments, also referred to as Mormon undergarments or Mormon underwear, are undergarments worn by members of the Church of Jesus Christ of Latter-day Saints as a symbol of sacred covenants made with God. In Mormon culture, the term “garments” has been adopted to mean these special undergarments.
When members of the church participate in the ordinances of the Mormon temple for the first time, they begin wearing these undergarments in place of other underwear and promise to continue wearing them night and day for the rest of their lives. This represents a covenant with God that they will remain faithful and obedient to the commandments of God and to the special covenants made inside the temple.
The garments are white, symbolizing purity, (except for some designed to be worn by those in active military service, which are olive green) and are made of several different types of fabrics: cotton, cotton/polyester, silk, etc., for the wearer’s comfort, size, and climate conditions. There is a top and a bottom, the top covering the shoulders and the bottom extending to the knees. This is to promote modesty of dress. They are worn directly next to the skin and completely covered by outer clothing. They are removed when wearing them would be improper for the activity. Naturally, bathing and swimming necessitate their removal, but they may be removed for other strenuous activities, such as football, basketball, running, professional dance, or other 
vigorous exercise as deemed appropriate by the wearer.
The practice of wearing religious clothing began with Adam and Eve. The Bible states, “unto Adam also and to his wife did the Lord God make coats of skins, and clothed them” (Genesis 3:21), when they discovered their nakedness. Mormons wear their garments in this same context, as obedience to an instruction from God. Like those of the Jewish faith wearing the yarmulke or tzitzit, ministers or priests wearing a special collar, or the clothing worn by nuns, the undergarments worn by Mormons signify the specific religion to which they belong and are a symbol of devotion to God.