Objective: To identify the type and mechanism of trauma-based on patients’ characteristics at a tertiary hospital in Riyadh, Saudi Arabia. Methods: The study was a retrospective cohort observational study using the Trauma Registry of King Abdulaziz Medical City, Riyadh, Saudi Arabia. The study period was from January 2015 to December 2018. The data gathered were demographic information, mortality, type and mechanism of injury, Glasgow Coma Scale (GCS), Injury Severity Score (ISS) and the Triage Revised Trauma Scale (T-RTS). Categorical data are described with percentage and frequency, and numerical data with mean and standard deviation. A Chi-square was used to assess the relationship between the type of trauma and patient characteristics. A Fisher exact test was used to compare the type of injury with the other variables. A p-value of less than 0.05 was considered statistically significant. Results: A total of 4083 participants. The majority were male (79.9%, n=3263). Blunt trauma was the most prevalent type of injury (87.4%, n=3570, p<0.001). A motor vehicle accident was the most prevalent mechanism of injury (42.1%, n=1717). The highest proportion of trauma per age group was in the 21-30 year age group (32.6%, n=1331). The lowest GCS and RTS mean scores were observed in blunt trauma (p<0.001 and 0.001 respectively). In addition, the highest ISS mean score was observed in the blunt trauma subgroup (p<0.001). Conclusion: The study highlights the type and mechanism of trauma at KAMC in Riyadh, Saudi Arabia, based on gender, age groups, types of trauma and mechanisms of injury. This data will be a valuable resource for the local healthcare system.