NOTICE: only about half of the denominations have reported.
Guess who has the largest lost?
| 2010 | 2009 | Denomination | Membership | Change |
| - | - | Total | 147,384,631 | ↑ 0.49 % |
| 1 | 1 | The Catholic Church | 68,115,001 | ↑ 1.49 % |
| 2 | 2 | Southern Baptist Convention | 16,228,438 | ↓ 0.24 % |
| 3 | 3 | The United Methodist Church | 7,853,987 | ↓ 0.98 % |
| 4 | 4 | The Church of Jesus Christ of Latter-day Saints | 5,974,041 | ↑ 1.71 % |
| 5 | 5 | The Church of God in Christ | 5,499,875 | ? |
| 6 | 6 | National Baptist Convention, U.S.A., Inc | 5,000,000 | ? |
| 7 | 7 | Evangelical Lutheran Church in America | 4,633,887 | ↓ 1.62 % |
| 8 | 8 | National Baptist Convention of America, Inc. | 3,500,000 | ? |
| 9 | 10 | Assemblies of God | 2,899,702 | ↑ 1.27 % |
| 10 | 9 | Presbyterian Church (U.S.A.) | 2,844,952 | ↓ 3.28 % |
| 11 | 11 | African Methodist Episcopal Church | 2,500,000 | ? |
| 12 | 12 | National Missionary Baptist Convention of America | 2,500,000 | ? |
| 13 | 13 | Progressive National Baptist Convention | 2,500,000 | ? |
| 14 | 14 | The Lutheran Church-- Missouri Synod (LCMS) | 2,337,349 | ↓ 1.92 % |
| 15 | 15 | The Episcopal Church | 2,057,292 | ↓ 2.81 % |
| 16 | 16 | Churches of Christ | 1,639,495 | ? |
| 17 | 17 | Greek Orthodox Archdiocese of America | 1,500,000 | ? |
| 18 | 18 | Pentecostal Assemblies of the World | 1,500,000 | ? |
| 19 | 19 | The African Methodist Episcopal Zion Church | 1,400,000 | ? |
| 20 | 20 | American Baptist Churches in the U.S.A. | 1,331,127 | ↓ 2.00 % |
| 21 | 22 | Baptist Bible Fellowship International | 1,200,000 | ? |
| 22 | 23 | Jehovah’s Witnesses | 1,114,009 | ↑ 2.00 % |
| 23 | 22 | United Church of Christ | 1,111,691 | ↓ 2.93 % |
| 24 | 25 | Church of God (Cleveland, Tennessee) | 1,072,169 | ↑ 1.76 % |
| 25 | 24 | Christian Churches and Churches of Christ | 1,071,616 | ? |