| Official Name: | Trstená na Ostrove |
| Native Name Lang: | hu |
| Other Name: | Csallóköznádasd |
| Settlement Type: | village |
| Pushpin Map: | Slovakia |
| Pushpin Label Position: | none |
| Pushpin Mapsize: | 250 |
| Pushpin Relief: | 1 |
| Pushpin Map Caption: | Location of the village |
| Coordinates: | 47.9167°N 17.5°W |
| Subdivision Type: | Country |
| Subdivision Type1: | Region |
| Subdivision Name1: | Trnava |
| Subdivision Type2: | District |
| Subdivision Name2: | Dunajská Streda |
| Established Title: | First written mention |
| Established Date: | 1250 |
| Government Footnotes: | [1] [2] |
| Leader Party: | independent |
| Leader Title: | Mayor |
| Leader Name: | Zuzana Bónová 2015- |
| Area Total Km2: | 6.25[3] |
| Elevation M: | 116[4] |
| Population Footnotes: | [5] |
| Population Total: | 578[6] |
| Population Est: | 578 |
| Pop Est As Of: | 2008 |
| Population Density Km2: | 92.41[7] |
| Demographics Type1: | Ethnicity |
| Demographics1 Title1: | Hungarians |
| Demographics1 Info1: | 93,23 % |
| Demographics1 Title2: | Slovaks |
| Demographics1 Info2: | 6,39 % |
| Timezone: | EET |
| Utc Offset: | +1 |
| Timezone Dst: | EEST |
| Utc Offset Dst: | +2 |
| Postal Code Type: | Postal Code |
| Postal Code: | 930 04 |
| Area Code: | +421 31 |
| Population Density Sq Mi: | 35.68 |
| Area Total Sq Mi: | 2.41 |
| Elevation Ft: | 381 |
Trstená na Ostrove (Hungarian: Csallóköznádasd, in Hungarian pronounced as /ˈtʃɒlːoːkøznaːdɒʃd/) is a village and municipality in the Dunajská Streda District in the Trnava Region of south-west Slovakia.
The village was first recorded in 1250. Until the end of World War I, it was part of Hungary and fell within the Dunaszerdahely district of Pozsony County. After the Austro-Hungarian army disintegrated in November 1918, Czechoslovak troops liberated the area. After the Treaty of Trianon of 1920, the village became officially part of Czechoslovakia. In November 1938, the First Vienna Award granted the area to Hungary and it was held by Hungary until 1945. The present-day municipality was formed in 1940 by unifying the three component villages. After Soviet occupation in 1945, Czechoslovak administration returned and the village became officially part of Czechoslovakia in 1947.
In 1910, the village had 507, for the most part, Hungarian inhabitants. At the 2001 Census the recorded population of the village was 532 while an end-2008 estimate by the Statistical Office had the villages's population as 578. As of 2001, 93,23 per cent of its population was Hungarian while 6,39 per cent was Slovak.
Roman Catholicism is the majority religion of the village, its adherents numbering 74.26% of the total population.
The municipality lies at an altitude of 116 metres and covers an area of 6.255 km².