The present study aimed to investigate the effects of various zinc concentrations (2.5 mg/l to 80 mg/l) on biomass, chlorophyll a, total carbohydrate and total protein contents of 10 cyanobacterial species. Biomass, chlorophyll a and carbohydrate content in all of cyanobacterial species were measured by spectrophotometric method. Zinc is toxic to these organisms causing severe inhibition of such physiological process as growth, chlorophyll a, carbohydrate and protein contents at concentrations less than 10 mg/l. Anabaena sp. GO1 and Gloeothece sp. GO9 were partly stimulated at lower zinc concntration (2.5 mg/l). In the high concentrations of zinc is more than 10 mg/L, biomass and other parameters of all cultures were completely reduced, except Anabaena sp. GO2 species