A series of fifteen chiral 1,2,3,4-tetrahydroisoquinoline (THIQ) derivatives have been synthesized and their antiproliferative properties have been studied. The in vitro screening was performed against five cancer cell lines; MCF-7 (breast cancer), A549 (lung cancer), DU-145 (prostate cancer), Hela (cervical cancer) and HepG2 (liver cancer). Most of the compounds showed promising activity with IC50 Values ranging from 0.72 to 92.6 μM. Among them, compounds 9a and 9b have shown significant activity against human prostate cancer cell line, i.e., DU-145 with IC50 value 0.72 and 1.23 μM respectively. To investigate the mechanism of action, detailed biological studies of compounds 9a and 9b were carried out on the human prostate cancer cell line, DU-145. Flow cytometric analysis revealed that these compounds induced cell cycle arrest at G2/M phase. Tubulin polymerization assay and immunofluorescence analysis results suggested that these compounds effectively inhibit microtubule assembly formation in DU-145. The apoptosis inducing properties were evaluated by DNA fragmentation analysis, Caspase-3 activity assay, Annexin V-FITC assay and Western blot analysis of proapoptotic protein, Bax and antiapoptotic protein Bcl-2.