Synthesis of β -carotene and chlorophylls in Dunaliella salina cells grown on whey, fermentation liquor and molasses were studied. The obtained results indicated that : [1] Fermentation liquor at concentration of 0.4% in 1/4 MH medium could replace the original MB medium. This state of culturing will save the chemicals used in the MR medium. [2] The amount of β-carotene synthesized in the presence of whey and fermentation liquor after 8 days of culturing were higher than the other culture treatments. [3] CaC1₂.2H₂O was found to be a significant factor for the synthesis of β -carotene in Dunaliella salina. [4] NaC1 was the most significant factor affecting β -carotene synthesis in Dunaliella salina. [5] β -carotene optimization obtained at a medium where all the factors were absent except NaCl.