Abstract: A few substances in the human diet have been identified as anticarcinogens but most of them are present in trace concentrations. Lipid preparations enriched in biologically active fatty acids like CLA, VA, EPA and DHA were used for Bioactive Lipid Complexes (BLCs) preparation. The compounds were examined for their antiproliferative activity in vitro against human lung (A549), melanoma (Hs294T), colon (HT-29), breast cancer (MCF-7) and promyelocytic leukemia (HL-60) cells. All compounds were also tested in combined treatment with several cytostatic agents. From all tested enriched lipid preparations and bioactive lipid complexes the compound BLC-2 containing 36.7% of CLA and 45.3% of EPA+DHA revealed the highest antiproliferative activity in tested human cancer models. Its activity was comparable to this of CLA-1 (98% c9, t11 C18:2 CLA) used alone as a reference. The results indicate that anti-proliferative activity of unsaturated fatty acid mixtures is associated with their composition.