The cytogenetic studies conducted on radicular meristems of Veronica officinalis vitro-plants aim at indicating whether and to what extent the nutritive medium and the in vitro culture conditions influence the mitotic activity of cells. The investigation of the cytogenetic samples demonstrated the fact that the mitotic activity in radicular meristems is normal and there are no significant events. The mitotic index (MI) was calculated for the vitro-plants investigated and their value varied according to the hormonal formula used in preparing the nutritive medium. The lowest MI (30.70) was calculated in the case of vitro-plants obtained on the MS medium supplemented with 1mg/l BAP and 0.5 mg/l IBA, and the highest MI value IM (45.63) was calculated for regenerants obtained on BA1 variant (1mg/l BAP and 0.1 mg/l IAA). Concerning the distribution of mitotic division phases, cells were observed to be predominant in prophases, followed by metaphases, telophases and anaphases at the majority of the radicular meristems of the vitro-plants studied. The frequency and spectrum of chromosomal aberrations also varied according to the nutritive variants on which the vitro-plants were regenerated. The spectrum of chromosomal anomalies involved anaphases with: (simple and multiple) bridges, retarding chromosomes, fragments, delayed and expelled chromosomes and cells (prophases and interphases) with micronuclei. In the case of the in vitro culture technology applied for cloning the species Veronica officinalis, the cell division has not been disturbed, the values of the mitotic index calculated for the regenerated vitro-plants on the mediums with phytohormones being proximate to the ones of MS medium regenerants without phytohormone supplements. The number of cells identified with chromosomal aberrations was relatively close to the one of control vitro-plants
