Microalgae are the primary source of food for Artemia franciscana. In turn, Artemia serve as live food for various species in culture. The chemical composition of Artemia is of great importance because it affects the nutritional quality of the organisms produced in aquaculture systems. For this reason, the present study aimed to characterize the nutritional value, proximal composition, concentration of chlorophyll a and b, and total carotenoid content in the microalgae Thalassiosira weissflogii, Chaetoceros muelleri, Tetraselmis suecica, and Nannochloropsis sp., which were used to feed juvenile A. franciscana for 6 h. Artemia juveniles fed with these microalgae species exhibited higher concentrations of proteins, carbohydrates, lipids, chlorophyll a and b, and total carotenoids than those in the control. The organisms fed with Tetraselmis suecica presented the highest content of chlorophyll b, while those fed with Thalassiosira weissflogii and Chaetoceros muelleri showed the highest values of total carotenoids and chlorophyll a.