Olive tree (Olea europaea L) is an economically significant fruit species of the Mediterranean and the mediterranean area of the Croatia. The irrigation of olive trees is an indispensable agrotechnical intervention by which we maintain the yield and economic effectiveness of olive oil production. The aim of the paper was to determine how different amounts of water during irrigation affect morphological characteristics fruit and pits. The research was conducted on island Dugi otok in the place Žman. The field experiment set on the coratina variety, on 24 olive trees, in four variants with three replicates. For morphological measurements the fruits were sampled from the middle part of the fruiting branch, while in the sample was 40 fruits. From the morphological characteristics of the fruit and stone were measured: fruit weight, fruit length, fruit width, ratio of fruit length and width, fruit pulp content, fruit pulp mass, stone mass, stone length, stone width, and ratio of stone length and width. Statistical data was performed by SigmaPlot11 programme and for comparison of mass, width, length, ratio of length and width and content of fruit pulp and stone Kruskal - Wallis one-way analysis of variance was used. The results of the study obtained that the increases in volume of water for irrigation did not affect the increase of: fruit length, ratio of fruit length and width, stone mass, stone width, stone length, ratio of stone length and width and maturity index. However, the increased amount of water had a significant effect on the increase of: fruit weight, fruit width, fruit pulp weight and fruit pulp content. The results obtained are in agreement with literature data and results from previous researches, except for the maturity index.