In this experiment seventeen Pedunculate oak trees (Quercus robur L.) were observed, located in an alley on the Boulevard of Vojvode Stepe (N 45°25'61.75", E 19°79'73.47") in Novi Sad, Serbia. From each tree, fifty acorns were randomly collected for the purpose of researching the variability of the genotypes based on the morphological characteristics of their fruits. The characteristics researched were the length and width of the fruit (mm, respectively), coefficient of elongation (ratio of the fruit length and width) and the weight of the fruit (g). Results of the one-way ANOVA show that there are statistically significant differences between the fruits of the observed Pedunculate oak genotypes. In the case of the coefficient of the elongation, the calculated F value turned out to be the highest (F=99,36), and it is on the level of statistical significance p<0.001. For the length of the fruit the determined value of F=97.86 is on the level of significance p<0.001, for the weight of the fruit F=5.884 is on the level of significance p<0.05, but the differences between the mean values of the width of the fruits are not shown as statistically significant. The analysis of the data from this research shows that genotypes 1, 2, 6, 11, 12, 13, 16 and 17 stands out from the others based on the desired characteristics of their fruits, and they present an interesting base for further research. In the following period experiments will be conducted regarding the effects of seed dimensions on the morphological characteristics of Quercus robur L. seedlings, and the resistance of seedlings to abiotic factors of stress (draught, etc.).