This is a list of member states of the Organisation of Islamic Cooperation sorted by their estimated population. It is sourced from the global list of countries by population page, as of July 2008[update].
| Rank | Country | Population |
|---|---|---|
| 1 | Indonesia | 231,627,000 |
| 2 | Pakistan | 163,707,000 |
| 3 | Bangladesh | 158,665,000 |
| 4 | Nigeria | 148,093,000 |
| 5 | Egypt | 75,498,000 |
| 6 | Turkey | 71,751,100 |
| 7 | Iran | 70,495,782 |
| 8 | Algeria | 33,858,000 |
| 9 | Morocco | 31,224,000 |
| 10 | Sudan | 30,894,000 |
| 11 | Uganda | 30,884,000 |
| 12 | Iraq | 28,993,000 |
| 13 | Uzbekistan | 27,372,000 |
| 14 | Malaysia | 27,170,000 |
| 15 | Afghanistan | 27,145,000 |
| 16 | Saudi Arabia | 24,735,000 |
| 17 | Yemen | 22,389,000 |
| 18 | Mozambique | 21,397,000 |
| 19 | Syria | 19,929,000 |
| 20 | Côte d'Ivoire | 19,262,000 |
| 21 | Cameroon | 18,549,000 |
| 22 | Kazakhstan | 15,422,000 |
| 23 | Burkina Faso | 14,784,000 |
| 24 | Niger | 14,226,000 |
| 25 | Senegal | 12,379,000 |
| 26 | Mali | 12,337,000 |
| 27 | Chad | 10,781,000 |
| 28 | Tunisia | 10,327,000 |
| 29 | Guinea | 9,370,000 |
| 30 | Benin | 9,033,000 |
| 31 | Somalia | 8,699,000 |
| 32 | Azerbaijan | 8,467,000 |
| 33 | Tajikistan | 6,736,000 |
| 34 | Togo | 6,585,000 |
| 35 | Libya | 6,160,000 |
| 36 | Jordan | 5,924,000 |
| 37 | Sierra Leone | 5,866,000 |
| 38 | Kyrgyzstan | 5,317,000 |
| 39 | Turkmenistan | 4,965,000 |
| 40 | United Arab Emirates | 4,380,000 |
| 41 | Lebanon | 4,099,000 |
| 42 | Palestinian territories | 4,017,000 |
| 43 | Albania | 3,190,000 |
| 44 | Mauritania | 3,124,000 |
| 45 | Kuwait | 2,851,000 |
| 46 | Oman | 2,595,000 |
| 47 | Gambia | 1,709,000 |
| 48 | Guinea-Bissau | 1,695,000 |
| 49 | Gabon | 1,331,000 |
| 50 | Qatar | 841,000 |
| 51 | Djibouti | 833,000 |
| 52 | Bahrain | 760,168 |
| 53 | Guyana | 738,000 |
| 54 | Comoros | 682,000 |
| 55 | Suriname | 458,000 |
| 56 | Brunei | 390,000 |
| 57 | Maldives | 306,000 |
| Total | 1,465,753,050 |