A series of novel pyrrolidinedione-thiazolidinones was synthesized and subjected to physico-chemical characteristics. They were screened on a panel of cell lines representing different types of cancer, as well as normal human keratynocytes and lymphocytes of peripheral human blood. High antiproliferative activity of 1-(4-chlorophenyl)- and 1-(4-hydroxyphenyl)-3-{5-[(Z,2Z)-2-chloro-3-(4-nitrophenyl)-2-propenylidene]-4-oxo-2-thioxothiazolidin-3-yl}-1-(4-hydroxyphenyl)-pyrrolidine-2,5-diones 2a and 2b was revealed along with satisfactory cytotoxicity characteristics. Human T-leukemia cells of Jurkat line were the most sensitive to the action of 2a, 2b and 5-(2-allyloxybenzylidene) derivative 2f. At the same time, synthesized compounds demonstrated low toxicity towards normal human keratinocytes of HaCaT line and mitogen-activated lymphocytes of peripheral blood of healthy human donor. The compounds 2а and 2b demonstrated high selectivity (SI >9.2) towards studied leukemia, lung, breast, cervical, colon carcinoma and glioblastoma cells. Compounds 2a, 2b induced mitochondria-dependent apoptosis in treated Jurkat T-cells via increasing the level of proapoptotic Bax and EndoG proteins, and decreasing the level of antiapoptotic Bcl-2 protein. The cytotoxic action of compounds 2a, 2b towards Jurkat T-cells was associated with the single-strand brakes in DNA and its inter-nucleosomal fragmentation, without significant intercalation of these compounds into the DNA molecule. Compounds 2a, 2b did not induce significant DNA damage and changes in morphology of mitogen-activated lymphocytes of peripheral blood of healthy donor. Altogether, these data demonstrated anticancer potential of novel hybrid pyrrolidinedione-thiazolidinones which were relatively non-toxic for normal human cells.