Background: An increase in the number of visitors to the emergency department (ED) leads to overcrowding, long wait, and patient dissatisfaction. It is important to implement the decision-making process to avoid congestion and nonurgent cases. This study aims to assess patients\' knowledge and attitude about the triage system and waiting times in ED. Methods: This was a cross-sectional study conducted at the ED at Prince Mohammed bin Abdulaziz Hospital, Riyadh, Saudi Arabia. Data were collected using an online questionnaire form for all participants who met the inclusion criteria. Results: In this study, 389 participants with mean age of 33.77 (SD =12.96) years were included, of them 54.2% were males. Moreover, only 15.2% of patients reported having primary care doctor or health providers among whom 41.9% reported that they tried to call their primary care doctor before coming to the ED. Moreover, 66.2% of participants reported having no knowledge about triage. Furthermore, 57% of participants wanted to know how long other patients have been waiting. Moreover, results showed that the most important information required by the patients was the periodic updates from ED staff about the delays (51.4%) followed by information about the health care system and how to find a primary care provider. Conclusion: Most of the population were unaware of the triage and its definition; however, most of the participants had good knowledge considering why some patients were seen before others. Finally, the waiting expectation of tests results was worse in this study, which reflected low satisfaction level.