BACKGROUND: Correct insulin injection practice is essential for better diabetic control. The aim of this study is to investigate the level of competency of prefilled insulin pen usage (injection technique and storage) among diabetes patients in Saudi Arabia. METHODS: A cross-sectional survey between March 2017 to July 2017 of randomly selected patients with diabetes attending Diabetes Treatment Center, Prince Sultan Military Medical City, Saudi Arabia, who are actively using a prefilled insulin pen, were interviewed to complete a pre-structured questionnaire to assess the competency of using the insulin pen. The contents of the questionnaire addressed the 6 competency components according to manufacturer recommendation (priming, count time, storage, using new needles, a store with no needles, and discard date), background, clinical and metabolic data. Results of the questionnaire were analyzed to identify common pitfalls and were also contrasted with background clinical and metabolic data. RESULTS: 165 patients with diabetes (aged 14-70yrs) were interviewed for the study and all questioners completed properly. Only 14 (8.5%) patients were following all of the six competency components. Count time 52 (31.6%) was the least followed competency component of the six, whereas discard date and storage of insulin pen were the most followed with 165 (100%) and 159 (96.4%), consecutively. Education was the only significant variable related to the following more than 3 of the competency components, and logistic regression showed the college or higher educated patients to be three times more likely follow more than 3 of the competency components. CONCLUSION: The study concluded that majority of patients are either ignoring or unaware of the major components of correct use of prefilled insulin in Saudi Arabia.