Introduction. Well informed and educated patients ideally manage to prevent or delay the onset of severe chronic diseases. With respect to erectile dysfunction (ED) this is of importance because ED is considered to herald debilitating cardiovascular diseases like coronary artery disease. Aim. This survey aimed to assess patient's knowledge about risk factors (RF) for ED and to identify their preferred source of information. Main Outcome Measures. Knowledge of RF for ED and sources used to gather information about ED as reported by patients with ED. Methods. Between July 2004 and June 2006, 126 patients who presented at our outpatient clinic for an assessment of their ED were prospectively evaluated. The patients received a questionnaire about their demographic and socioeconomic circumstances, their strategies to gather information about ED, and their knowledge of specific RF for this disease. The questionnaire was completed by 81 patients (64%). Results. Forty-one patients (51%) could not name one single RF for ED. Three men knew more than three RF. The two most popular sources of information were the Internet and general practitioners. Well-educated patients were significantly better informed than others. Patients using the Internet as source for health information were significantly younger and had a better knowledge about RF for ED compared to those not using the Internet. Conclusions. Patients' knowledge about RF for ED is poor. The Internet seems to be the most useful information source for patients with ED and is predominantly used by younger and better educated patients. Given that ED is considered to be a precursor lesion of severe cardiovascular diseases, patient information and education deserves more attention.