Eight of the 25 top denominations reported membership decreases in the past year, while the remaining 13 did not record membership updates during the period.
Overall, U.S. church membership rose 0.49 percent from 2009 to 2010.
The data was published in the latest Yearbook of American & Canadian Churches, released this month by the National Council of Churches, based in New York.
Membership in the Catholic Church rose nearly 1.5 percent to more than 68 million, the largest denomination by far in the country. The church rebounded from a slight drop last year.
The LDS Church saw a 1.7 percent increase in its U.S. membership to just under 6 million, while the Assemblies of God, a Pentecostal faith group, recorded a nearly 1.3 percent jump, to 2.9 million members.