Defoliation is a standard measure of removing the vine leaves in the zone cluster with the aim of achieving a better ripening of grapes, breathability, providing better protection from diseases such as gray mold, better development of shoots and other vegetative parts, and can be implemented in different terms. Numerous studies indicate that defoliation is a highly useful measure. The aim of this study was to determine the effect of different terms of defoliation on sugar content, total acidity and real acidity of must and content of total polyphenols and anthocyanins in the epidermis of Blaufränkisch cultivars (Vitis vinifera L.). The study was conducted during 2015. on experimental wineyard of Agricultural Faculty Osijek, located in Mandićevac, viticultural region Eastern Continental Croatia, Slavonia subregion, vineyards Đakovo. The experiment was design as a randomized complete block system with three variants in four replications (control treatment – no defoliation, defoliation immediately after pre-bloom – E-L phase 27 and defoliation before the start of veraison – E-L phase 34). There was no significant differences for parameters of the sugar content in the must, total acidity and real acidity of must. Also content of total polyphenols shows no statistically significant differences between the control (417 mg/kg) and treatment with defoliation after the end of flowering (426 mg/kg), but significanty higher content of total polyphenols, compared to the two previous treatment ,was measured at treatment with defoliation before the start of veraison (470 mg/kg). The total content of anthocyanins was significantly different. Early defoliation after completion of flowering shows reduce of content of anthocyanins (461 mg/kg), and defoliation before the veraison leads to the opposite effect and a significant increase of total anthocyanins (569 mg/kg), while in the control treatment was 530 mg/kg.