Objective:To identify the in vitro antiplasmodial activity of seaweed plants against Plasmodium falciparum strains.Methods:A total of eight seaweeds were collecled from Kanvakumari district,Tainilnadu,India.The in vitro antiplasmodial activity was performed in 96 well plates against Plasmodium falciparum,and preliminary phytochemcial analysis were performed for the extracts.Results:Of the selected plants Enteromorpha intestinalis(2.61%) showed maximum percentage of extraction.The minimum concentration of inhibitory(IC_(50)) value was observed with Chaetomorpha antennina[(26.37±4.14)μg/ml.]further,the positive controls such as chloroquine and artemether showed antiplasmodial activities(IC_(50)) with(19.10±5.93) and(6.03±0.21)μg/mL concentrations,respectively.The preliminary phytochemical analysis of the seaweed extracts showed a variety of phytochemical constituents such as carboxylic acids,phenols,protein, resins,steroids and sugars.Conclusions:The antiplasmodial activity of the seaweed extract might due to the presence of sugars and phenolic compounds.From the present findings,it is concluded that,the seaweed extract of Chaetomorpha antennina can be further used as a putative antiplasmodial drugs in near future. Objective: To identify the in vitro antiplasmodial activity of seaweed plants against Plasmodium falciparum strains. Methods: A total of eight seaweeds were collecled from Kanvakumari district, Tainilnadu, India. The in vitro antiplasmodial activity was performed in 96 well plates against Plasmodium falciparum, and Preliminary phytochemcial analysis were performed for the extracts. Results: Of the selected plants Enteromorpha intestinalis (2.61%) showed maximum percentage of extraction.The minimum concentration of inhibitory (IC_ (50)) value was observed with Chaetomorpha antennina [(26.37 ± 4.14) μg / ml.] Further, the positive controls such as chloroquine and artemether showed antiplasmodial activities (IC 50) with (19.10 ± 5.93) and (6.03 ± 0.21) μg / mL concentrations, respectively. The preliminary phytochemical analysis of the seaweed extracts showed a variety of phytochemical constituents such as carboxylic acids, phenols, protein, resins, steroids and sugars. Conclusions: The antiplasmodial activity of the s eaweed extract might due to the presence of sugars and phenolic compounds. From the present findings, it is said that, the seaweed extract of Chaetomorpha antennina can be further used as a putative antiplasmodial drugs in near future.