Demographic history of Syrmia
This is demographic history of Syrmia.
In 11th-12th century, according to Hungarian sources, region of Syrmia had partially Slavic and partially mixed Slavic-Hungarian population.  Around 1154, Al-Idrisi, a Muslim geographer, described Manđelos as a rich town, whose inhabitants pursued a rather "nomadic way of life". By some opinions, Idrisi might have referred simply to stock-breeding that played an important role among the Hungarian inhabitants of the entire region of Syrmia This fact was confirmed later by several Byzantine authors in the 12th century (Ioannes Kinnamos, Niketas Choniates, Patriarch Michael).
In 1495, the area of Syrmia had a mixed population of Croats, Hungarians and Serbs. 
According to the census from 1857, 59.4% of population of the part of Syrmia under civil administration and 63.2% of population of the part of Syrmia under military administration (Petrovaradin regiment) were ethnic Serbs. The second largest ethnic group were Croats, while other ethnic groups were Germans, Hungarians, etc.
- Serbian language = 183,109 (44.20%)
- Croatian language = 106,198 (25.64%)
- German language = 68,086 (16.44%)
- Hungarian language = 29,522 (7.13%)
- Slovak language = 13,841 (3.34%)
- Rusyn language = 4,642 (1.12%)
In 1931, the population of Syrmia included:
- Serbs = 210,000
- Croats = 117,000
- Germans = 68,300
- Hungarians = 21,300
- Slovaks = 15,300
- Ukrainians = 5,300
In 1971, the population of the Serbian part of Syrmia (excluding City of Belgrade's municipalities of Novi Beograd and Zemun which are geographically part of Syrmia) numbered 313,926 inhabitants, including:
- Serbs = 228,609 (72.84%)
- Croats = 38,389 (12.23%)
- Slovaks = 14,056 (4.48%)
- Hungarians = 9,376 (2.99%)
- Yugoslavs = 9,086 (2.89%)
- Rusyns = 3,403 (1.08%)
- Ukrainians = 1,512 (0.48%)
- Montenegrins = 1,400 (0.44%)
- Slovenes = 1,065 (0.34%)
- Macedonians = 1,023 (0.33%)
According to the 2011 census in Serbia, the population of the Serbian part of Syrmia (excluding City of Belgrade's municipalities of Novi Beograd, Zemun and Surčin which are geographically part of Syrmia) numbered 370,619 people and is composed of:
- Serbs = 310,376 (83.74%)
- Croats = 11,445 (3.08%)
- Slovaks = 9,216 (2.48%)
- Romani people = 6,984 (1.88%)
- Hungarians = 4,901 (1.32%)
According to the 2011 census in Croatia, the population of the Croatian Vukovar-Srijem county, numbering 179,521, is composed of:
- Croats = 142,135 (79.17%)
- Serbs = 27,824 (15.5%)
- Hungarians = 1,696 (0.94%)
- Rusyns = 1,427 (0.79%)
- Slovaks = 1,185 (0.66%)
- Osman Karatay, In search of the lost tribe: the origins and making of the Croatian nation, Ayse Demiral, 2003, p. 46
- Derek Keene, Balázs Nagy, Katalin Szende, Segregation, integration, assimilation: religious and ethnic groups in the medieval towns of Central and Eastern Europe, Ashgate Publishing, Ltd., 2009, p. 75-76.
- Dr. Aleksa Ivić, Istorija Srba u Vojvodini, Novi Sad, 1929.
- Károly Kocsis: Ethnic Geography of the Hungarian Minorities in the Carpathian Basin
- Vasilije Đ. Krestić, Iz prošlosti Srema, Bačke i Banata, Beograd, 2003.
- Szerém (Srijem) County
- Jovan Pejin, Kolonizacija Hrvata na srpskoj zemlji u Sremu, Slavoniji i Baranji, Sremska Mitrovica, 1992.
- Dr. Branislav Bukurov, Bačka, Banat i Srem, Novi Sad, 1978.