US MEMBERSHIP CHURCH RANKING: Largest 25 Churches  
Denomination Name Current Ranking (Ranking in 2007 ed.) Inclusive Membership Percentage Increase/Decrease
The Catholic Church 1(1)             67,515,016 0.87%
Southern Baptist Convention 2(2)             16,306,246 0.22%
The United Methodist Church 3(3)                7,995,456 -0.99%
The Church of Jesus Christ of Latter-day Saints 4(4)                5,779,316 1.56%
The Church of God in Christ 5(5)                5,499,875 0.00%
National Baptist Convention, U.S.A., Inc. 6(6)                5,000,000 0.00%
Evangelical Lutheran Church in America 7(7)                4,774,203 -1.58%
National Baptist Convention of America, Inc. 8(8)                3,500,000 0.00%
Presbyterian Church (U.S.A.) 9(9)                3,025,740 -2.36%
Assemblies of God 10(10)                2,836,174 0.19%
African Methodist Episcopal Church 11(11)                2,500,000 0.00%
National Missionary Baptist Convention of America 11(11)                2,500,000 0.00%
Progressive National Baptist Convention, Inc. 11(11)                2,500,000 0.00%
The Lutheran Church– Missouri Synod (LCMS) 14(14)                2,417,997 -0.94%
Episcopal Church 15(15)                2,154,572 -4.15%
Churches of Christ 16(16)                1,639,495 0.00%
Greek Orthodox Archdiocese of America 17(17)                1,500,000 0.00%
Pentecostal Assemblies of the World, Inc. 17(17)                1,500,000 0.00%
The African Methodist Episcopal Zion Church 19(19)                1,443,405 0.21%
American Baptist Churches in the U.S.A. 20(20)                1,371,278 -1.82%
United Church of Christ 21(21)                1,218,541 -0.47%
Baptist Bible Fellowship International 22(22)                1,200,000 0.00%
Christian Churches and Churches of Christ 23(23)                1,071,616 0.00%
The Orthodox Church in America 24(24)                1,064,000 0.00%
Jehovah’s Witnesses 25(25)                1,069,530 2.25%
TOTAL       147,382,460 0.24%
Percentage changes in italic/bold signify that membership was not updated from previous reported

(This is taken from a report from the National Council of Churches. Just think if Joseph Smith was looking for a church today!)

P.S. It was brought to my attention that the column on the far left that contains percentage of increase or decrease in conversions isn’t showing up.  I reccomend clicking on this link: http://www.ncccusa.org/news/080215yearbook1.html to view a more indepth study online.

Jehovah’s Witnesses had the best conversion rate last year with 2.25% and LDS had the next with 1.56%.

Episcopal Church had the worst with a -4.15% drop and Presbyterian Church was next with over -2%.