Although patients with venous leg ulcers are involved in ulcer management, little is known about why and how these patients self-treat their ulcers without direct supervision by health professionals. Yet patients' knowledge of ulcer management can be important for achieving ulcer closure and/or preventing recurrence. This study thus investigates the effects of an educational intervention on knowledge of self-care among patients with venous leg ulcers, mainly on wound dressing practice, compression therapy, physical activity and nutrition. This research was conducted in three outpatient hospitals in central Croatia. An educational brochure was made and distributed to patients; patients were surveyed about caring for venous leg ulcers before the brochure was distributed and after 3 months. In total, 208 patients were involved in the study: 112 in the experimental group and 96 in the control group. The educational intervention increased awareness of compression therapy, knowledge of recurrence prevention, appropriate lifestyle habits, and warning signs related to venous leg ulcers. Patient education on illness and self-care is necessary to achieve positive effects in self-care knowledge. In this study, patients learned how to change dressings, learned how to improve their lifestyle, and were empowered to deal with their illness.