Abstract In this work 36 algae species were collected on the coastline between Tekirdag and Istanbul. There were 12 Chlorophyceae, 10 Phaeophyceae and 14 Rhodophyceae amongst them. The algae were f irst determined in Sea of Marmara are: Gigartina teedii, Cystoseira opuntioides, Lithothamnion lichenoides, Hildenbrandia prototypus, Rhodymenia corallicola.