Istria is the northernmost olive-growing region in Croatia and belongs to the cold olive-growing zone according to worldwide data. This paper presents the morphological characteristics of fruits and pits of autochthonous and introduced olive varieties in organic cultivation in the Buje area in the climatological year 2022. The autochthonous varieties: 'Istarska bjelica', 'Črnica' and 'Porečka rosulja' and the introduced varieties: 'Leccino', 'Pendolino', 'Moraiolo' and 'Frantoio' were morphologically characterised. The presentation of the morphological characteristics of fruits and endocarps was done according to the guidelines of the methodology for primary characterisation of olive varieties according to the IOC. The variety 'Porečka Rosulja' had the highest fruit weight, the variety 'Pendolino' the lowest. In the varieties 'Porečka Rosulja' and 'Pendolino' the maximum diameter is closer to the base of the fruit, while in the other observed varieties it is in the middle of the fruit. The cultivars 'Črnica', 'Leccino' and 'Moraiolo' have no bulge on the top of the fruit, the cultivars 'Pendolino' and 'Frantoio' have a barely visible bulge, and the cultivars 'Porečka rosulja' and 'Istarska bjelica' have a bulge. The cultivars 'Istarska bjelica', 'Leccino' and 'Moraiolo' have the same colouration along the entire length of the fruit when ripe, in the cultivar 'Frantoio' it is closer to the base of the fruit and in the other cultivars the colouration of the fruit starts closer to the tip of the fruit. The varieties observed indicate intravarietal morphological variability in fruit and endocarp characteristics.