We evaluated the effect of a telemedicine system on maternal and fetal outcome in women with diabetes. A total of 276 pregnant women were enrolled in the study. Women were sequentially assigned to a telemedicine or a control group. There were 88 women with gestational diabetes in the telemedicine group and 115 in the control group; there were 17 women with type 1 diabetes in the telemedicine group and 15 in the control group. Women in telemedicine groups were asked to submit their blood glucose data every week, and had a medical examination at the diabetes clinic once a month. Women in the control groups had a medical examination every two weeks. Subjective outcomes were investigated using the following questionnaires: CES-D for depression, SF-36 for health-related quality of life (QoL), Stress and Distress for the impact of diabetes. Clinical variables and pregnancy outcomes were no different between the two telemedicine groups, whereas women with gestational diabetes in the telemedicine group had a better metabolic control in the 3rd trimester and a lower rate of caesarean sections and macrosomia. As for QoL, women in the telemedicine groups showed lower levels of frustration and concerns about their diabetes, and a better acceptance of their diabetic condition. A questionnaire on the use of the telemedicine system showed a high degree of acceptance (85%). Both telemedicine groups had fewer check-ups at the diabetes clinics. The use of a telemedicine system for glucose monitoring improved pregnancy outcome in women with gestational diabetes and improved QoL in all diabetic pregnancies.