Background: diabetic foot ulcer is a major health problem around the world with a high morbidity and mortality rates. The good knowledge and practice pattern could decrease the diabetic foot ulcer complications. Objectives: this study aimedto evaluate knowledge of the diabetic patients regarding the complications of diabetic foot ulcer in Saudi Arabia (KSA). Patients and Methods: this isa cross sectional community based study conducted from March 2017 to July 2017 among 920 diabetic patients. The subjects were interviewed in the shopping malls, pharmacies and coffee shops and asked to fill out a pre-tested questionnaire about the knowledge of complications. Results: the duration of diabetes was more than 10 years among 65% of them. About 40.9% of subjects were using oral hypoglycemic agents, 57.8% were using insulin for management of diabetes. The most common diabetic complication was retinopathy, while the most common foot ulcer complication was foot numbness and stiffness. The level of knowledge was good among most of subjects (77%), while 23% had insufficient knowledge regarding the diabetic foot ulcer. The good awareness was significantly associated with higher educational levels. Conclusion: the level of awareness about complications of diabetic foot was sufficient among most of Saudi subjects. But, there was an urgent need for raising the awareness and identifying the risk factors, educating the patients through increasing the patients and doctors relationship. The knowledge alone was not sufficient for assessing the practice pattern thus major studies must be conducted to assess the knowledge, attitude and practice pattern among Saudi subjects.