There is studied progamic phase of the pollination of the local and introduced apricot (Prunus armeniaca L.) varieties using fluorescence microscopy [1, 2]. Fluorescence microscopy provides a relatively rapid and reliable method to determine self-(in)compatibility of apricot genotypes after in vivo experiences regarding pollination. The investigations also included its open pollination variant as control. As a rule, in self-compatible genotypes, developed on stigma pollen tubes reach the ovary in the majority of pistils, and also often rich the ovule. In self-incompatible varieties, growth of pollen tubes in the style is stopped along with formation of characteristic swellings. The research of the in vivo growth dynamics of the pollen tubes in experimental self-pollination showed that the highest level of efficiency was found in varieties: Auras, Bucuria, Detskii, Dionis, Krasnoshciokii, Kishiniovskii rannii, Kostiujenskii, Meteor, Melitopolskii pozdnii, Raduga, Saturn, Vimpel. The variety Nadejda and Vasile Cociu were self- and cross-pollinated with 3 autochthonous and 2 introduced varieties in order to investigate occurrence of incompatible pollen tubes in the style and their impact on fertilization success. Our results show that pollen tubes usually stop their growth in the third quarter of the style length. The highest percentage of them stopped the growth in the upper third of the style. As for the open pollination, percentages of incompatible pollen tubes in the upper part of the style by years were 12.0 - 14.0%, respectively. The occurrence of incompatible pollen tubes did not influence the fertilization success in studied interpollination variants.  In those variants, pollen tubes reached the ovary in the majority (60-100%) of pistils. They also often (from 40 to 95%) reached the ovule. The average number of pollen tubes at the base of the style ranged from 2.8 to 15.1, and at the ovule ranged from 0.5 to 3.0. Varieties were considered self-incompatible if the pollen tubes stopped their growth in the style, usually with forming swollen tips. Other important signs of incompatibility include twisted pollen tube growth and bifurcation of a pollen tube. Self-incompatibility was found in 15 of the apricot varieties studied: Aurora, Burevestnik, Erevani, Goldrich, Gvardeyskyi, Harglow, Hargrand, Harostar, Nadejda, Orangered, Robada, Traian, Sun Glo, Veecot, 1B49. In these cultivars, pollen tubes rarely reached the base of the style, while no pollen tube was found in the ovules. The number of pollen tubes at the base of the style ranged from 0.0 to 1.0. The site of inhibition of pollen tube growth in apricot differs from that normally associated with gametophytic incompatibility (4). Usually, pollen tubes mainly stop their growth in the upper third of the style. However, in our study, in most cases of self incompatibility, we observed that pollen tubes stopped growing in the lower half of the style. The results obtained in this study lead to the conclusion that self-incompatibility is frequent among new important apricot varieties from many international breeding programs.  Self-incompatibility is an undesirable trait in fruit crop production, because self-incompatible varieties cannot be grown in single-variety plantations, and it is necessary to provide additional adequate pollinators. Apricot flowering takes place in early spring and usually proceeds under unfavorable weather conditions that limit bees’ flight and optimal cross-pollination processes. Considering that selfincompatibility occurs frequently among newly created apricot varieties, care should be taken of variety partners’ selection for new orchard establishing. Self-compatibility continues to be considered the most important objective in apricot breeding programs, because such varieties can ensure more successful pollination, higher and more regular fructification.