Phenols are the most widespread secondary metabolites in the plant kingdom. Although not directly involved in the processes of photosynthesis and breathing, they play an important role in the survival of the plant itself. Primarily, they serve to protect the plant from abiotic and biotic stress. Numerous studies have identified anticancer, antiallergic, anti-inflammatory, antimicrobial, neuroprotective and many other positive properties of phenols. Due to the positive impact on human health, and because of the easy binding with many compounds (such as proteins), phenols are suitable for use in pharmaceutical, food and cosmetic industries. The subject of this research is to determine changes in the composition and content of phenolic compounds (flavanols, flavan-3-ols, hydroxycinnamic acid and hydroxybenzoic acid) present in the leaves of 10 indigenous and two introduced white varieties. The research took place at the Experimental station "Jazbina" during year 2017. The samples were collected periodically, starting with the completion of flowering vines to the technological maturity of the individual varieties. The leaves are then adequately stored, lyophilized and subjected to extraction. Extracts were analyzed with high performance liquid chromatography, and results were processed using an ANOVA test and Duncan Multiple Range test. Based on the results obtained, significant variability was found in the mass proportions of phenolic compounds between the varieties per individual sampling periods. Also, significant variability in the content of phenolic compounds within the same variety has been established during different sampling times.