Astaxanthin (ASX) is a red xanthophyll carotenoid found in various microorganisms and marine animals. ASX is also called the "super antioxidant" because it has the highest antioxidant activity among existing carotenoids. Studies have shown not only antioxidant properties but also antimicrobial, immunomodulatory, hepatoprotective, anticancer and antidiabetic properties of ASX. However, there is a limited number of studies examining the selective cytotoxic effects of ASX on cancer cells. The aim of this study was to determine the cytotoxic effects of ASX on cells representing common cancer types. For this, human breast (MCF-7), lung (A549), liver (HepG2), melanoma (VMM917), colon (WiDr) cancer and normal fibroblast cells were treated with different concentrations of ASX for 72 h and then the MTT assay protocol was applied. Cisplatin was used as a positive control in cytotoxicity experiments. The results showed that ASX had a dose-dependent cytotoxic effect on all studied cancer cell lines. However, the strongest selective cytotoxic effect of ASX was determined in A549 and WiDr cells compared to fibroblast cells. This study shows that selective cytotoxic effect of ASX should be investigated more extensively, especially in terms of lung and colon cancer.