OBJECTIVES:  To explore the patients and Knowledge about cost of medicines in Saudi Arabia METHODS:  It is a 4-months cross-sectional survey of patient and basic knowledge of medicines. The questionnaire consisted of two-part demographic information, and second part of forty-nine questions divided into four domains. It included basic information about medication, patient information about the drug related problem, patient information about drug-related cost, and patient perception of medications. MedlinePlus and DailyMed health information used. The 5-points Likert response scale system used. The survey distributed through social media and at 500-bed pediatrics and maternity hospital in Asir region, at ambulatory care pharmacy. The survey made an electronic format, and it analyzed domain three through survey monkey system RESULTS:  The total responders were (614) Saudi patient. The gender distribution 523 (86.7%) was female, and 91(13.3%) was male. The majority of them in age (18-44) 78.3%, and located at Asir region 325 (115%) and Riyadh region 163 (46.9%). The type of medications used was for Diabetic and Hypertension, Skin, Respiratory diseases. The responders showed good knowledge about drug storage at room temperature 380 (64.7%) or refrigerator 378 (64.7%), and how to behave with an expired medication 328 (59.85%). The patient had adequate information about drug and light exposure 335 (57.56%) while incomplete information about prescription prices 265 (44.9%). The responders showed that a missing of medication knowledge lead them to visit doctor clinic (20%), visit the pharmacy (32.4%), visit hospital emergency (7.4%), hospital admission (13.9%) or intensive care admission (4.3%). CONCLUSIONS:  The missing of drug information knowledge is burden cost on health care system. Drug-related prices and medication cost awareness are demanding for Saudi patient to prevent drug-related hospital admission, improve patient clinical outcomes and quality of life.