Background: Diabetic ketoacidosis (DKA) is considered to be a serious acute life-menacing complication of diabetes type (1) and type (2). The study aims to assess the level of awareness regarding DKA among diabetic patients in the Riyadh population. Methodology: The study is an institution-based cross-sectional study with a sample size of 150 participants. The participants are chosen through systemic random sampling, who have type (1) or type (2) diabetes mellitus patients and are 18–35 years of age. The medical personnel were excluded from the study. A self-administered, precoded, and pretested questionnaire was developed especially for this study after consulting literature and epidemiologists containing data about the risk factor, management, and complication. Data were analyzed using (SPSS). A P value of less than 0.05 was considered significant. Results: 38.67% (58) participants have poor awareness regarding complications, 67.34% (101) have poor knowledge regarding management, and 6% (9) participants have a good knowledge, 38% (57) participants have poor knowledge regarding risk factors and 30% (45) of the participants have good awareness. The relation between having a first degree relative with diabetes and awareness regarding management is significant with a P value of 0.022; 73% (110) of the participants had no relatives with diabetes mellitus and 71% (79) had a poor level of awareness regarding the management of DKA. However, 55% (22) of respondents who had relatives with diabetes mellitus also had a poor level of awareness regarding treatment. Conclusion: The majority of the participants had a poor level of awareness. There is a relationship between having a first-degree relative with diabetic mellitus and the level of awareness regarding DKA.