The aim of this work is to detect how 3,5-diacetamido-2,4,6-triiodosodium benzoate (sodium amidotrizoate), a synthetic derivative of the anti-auxin triiodonezoic acid (TIBA), influences the growth and content of primary metabolites in the green alga Chlorella vulgaris Beijerinck. It strongly suppressed cell number by 6–20%, chlorophyll a by 6–14%, chlorophyll b by 20–24%, total carotenoids by 7–13% and monosaccharides by 7–8% at the concentration of 10^-4 M, in comparison to the control. On the other hand, sodium amidotrizoate applied at lower concentrations (10^-7 – 10^-6 M) acted as a weak stimulator of analyzed biochemical compounds in algal cells. No statistically significant effect was detected with the application of sodium amidotrizoate at a concentration of 10^-8 M. It seems that sodium amidotrizoate plays an important role in algal growth and development and probably possesses anti-auxin activity, like TIBA.