The aim of this study was to investigate the effect of essential oils extracted from Origanum minutiflorum and Cyclotrichium niveum (Labiatae) plants to the vascularization systems of the chick embryos in a chorioallantoic membrane model. The aerial parts of O. minutiflorum and C. niveum were subjected to hydrodistillation. Essential oils were applied to the center of the blastodisc of 50 mu l using a precision micropipette prior to the transfer of shell-less cultures to the incubator. Antiangiogenic effect of essential oil of the study plants was determined with the use of chorioallantoic membrane model. Numbers of main, branching and capillary blood vessels were counted. In the statistical analysis, when the groups were compared with regard to the main blood vessel (MBV) and branch blood vessel (BBV) development, no significant difference (p > 0.05) was observed. However, when the groups were compared with regard to capillary vessel (CV) development, the difference between the data of the groups was found significant (p < 0.05). One of the tested compounds, C. niveum essential oils, showed antiangiogenic effect; while the other, O. minutiflorum showed no antiangiogenic effect. This study examined the effect of exposure to O. minutiflorum and C. niveum essential oils on extraembryonic vascular development in the chick embryo area vasculosa (AV) in shell-less culture for the first time. Essential oils extracted from C. niveum has antiangiogenic effect; while O. minutiflorum essential oils had no antiangiogenic effect.