The objective of this paper is to implement association rule mining in order to identify the underlying patterns in road crash injuries recorded in Greece, after separating them into subsets concerning the mainland and the island areas. To that end, an analysis of disaggregated data from the Hellenic Statistical Authority data file for killed, seriously and slightly injured road users was implemented for 2017-2019. The apriori rule was developed and a variety of association rules were obtained. Results indicated a strong association or concurrent presence of the contributory factors at various percentages in both mainland and island road crash injuries. It was also revealed that clear weather, urban area and male road users were dominant interconnected conditions that simultaneously exist in injury crashes.