In the present work, antagonistic effect of abscisic acid (ABA) and various plant growth regulators on cytogenetic activity in root meristem cells of barley (Hordeum vulgare L. cv. Bulbul 89) was compared. The seeds germinated in medium with ABA alone (25 mu M, micromolar), mitotic phases and mitotic aberrations were mounted on an Olympus CX41 microscope and photographed (100X) with a digital camera (Olympus C-5060). The results showed that mitotic index (MI) significantly decreased while chromosomal aberrations increased by approximately 70% as compared to control. However, all of the plant growth regulators (PGRs) studied [gibberellic acid- GA(3), Kinetin- KIN, benzyladenine- BA, ethylene- E, 24-epibrassinolide- EBR, triacontanol-TRIA and polyamines- PAs (cadaverine-Cad, putrescine- Put, spermidine- Spd, spermine- Spm)] revealed to a successful performance in ameliorating of the negative effect of ABA on these parameters. The data obtained in the present work showed that all stimulators used overcame the mitotic activity-preventive effect of ABA and the most effective stimulators were GA(3), KIN, BA and EBR, respectively. In addition, this study indicated that almost all stimulators were able to largely remove detrimental effect of ABA on chromosomes and the most prominent effect on this parameter was obtained with GA(3), KIN and TRIA.