A total of 175 patients with Types 1 and 2 diabetes in primary care and university hospital outpatient departments were randomized into a study group (n = 101) or usual care (n = 74). The study group used an e-health application with a diabetes management system and a home care link. Usual care did not involve e-health, i.e. the patients made regular general practitioner visits about every three months. After 12 months HbA1c decreased significantly in both groups of patients. The differences were small, but HbA1c was significantly lower in the study group than the controls. Diastolic blood pressure, fasting plasma glucose, serum total cholesterol, serum LDL-cholesterol and serum triglycerides were significantly lower in the study than in the control group. This was achieved with fewer visits by study patients to doctors and nurses. Use of e-health in diabetes care for 12 months was able to provide equivalent diabetic control to usual care, and improved cardiovascular risk factors.