Algae, although are the primitive thallophytic, autotrophic and aquatic organisms, they count a number of great economic importances in the present world.
Some of the economic importances of algae are as follows:
- Algae are the healthy source of carbohydrates, fats , proteins, vitamins A, B , C and E as well as the minerals like iron, potassium, magnesium, calcium, manganese and zinc .They are popular in developed countries as sea foods.
 - Algae are also used as fodder to feed livestocks such as cattle and chickens.
 - In fish farming, algae plays a very important role because many fish species consume algae as food and hence help in production process.
 - Algae help in maintaining the health of marine ecosystem as they absorb excessive CO2
 - Algae are rich in mineral, nutrients and are considered as good liquid fertilizer.
 - Blue green algae help to reduce alkanity of soil.
 - Water pollution is checked with the help of Algae like Euglena and Chlorella, that can easily change their colour. Algae are sensitive to pollution.
 - Many seeweeds such as Laminaria japonica and L.religiosa contain high percentage of iodine. This is why  they are used as medicine in powdered form for the treatment of goitre.
 - Lots of red algae such as Corallina are used to treat worm infections.
 - Laminaria and Ascophyllum (marine brown algae) possesses the antibiotic property.
 - Many aquatic algae are used to commercially produce agar- agar, an artificial nutrient media (carbohydrates) from it's gelatinous mucillage of outer body.