The grapevine is economically important crops for the area of Zadar County. In order to achieve good production results it is important to carry out agro – technical interventions care plantation. One such trait is the defoliation. Defoliation procedure is a green cut that removes 3 to 4 lower leaf on the vine. Measure of defoliation is applied to achieve the ligtness and brightness within the cane for getting harder berries, clogging higher sugar content in grapes. The aim of this study was to determine whether different terms of hand defoliation affect on the mechanical composition of the cluster and berry, yield per plant, the amount of sugar in the must and the total acidity of must on cultivar Syrah (Vitis vinifera L.). The study was conducted at the University vineyard Baštica 2016. located in the vine growing region Coastal Croatia, subregion Dalmatian zagora, vineyards Benkovac-Stankovci. The experiment was set up in three variants, or three random order in each row to 10 vine. Defoliation was carried out to the extent to which the present clusters (3-4 removed the bottom sheet), in the first version at the time of flowering in a row, in the second variant in the time patterns in the second row and the third variant was a control, or a variant on which is not conducted defoliation. At the time of harvest picked the 10 clusters with selected 10 vines within each row. When measuring the mechanical composition of the cluster and berry separated to each part and weight. Counting and computation to calculate the elements of fertilitiy based on the load and the number of cane developed clusters. The sugar content in the must is measured with refractometer of Oechsle's scale, a total acid titration using NaOH. Based on the one year studies and the results obtained, defoliation has had no effect on the mechanical composition of the cluster and berries, as well as the yield per plant. In contrast, administration of defoliation at the flowering time and the time patterns resulted in higher sugar content compared to the control treatment.