Carbohydrates (CHO) are a major determinant of post-prandial blood glucose in the diet of people with Type 1 diabetes mellitus, but patients frequently fail to evaluate CHO food content. Poor education is thought to contribute heavily to this failure. Our aim was to plan and evaluate a simple educational program to improve dietary knowledge and teach how to count CHO in Type 1 diabetic subjects. Forty-eight patients (age 27+/-1 yr, diabetes duration 11+/-1 yr, HbA1c 9%) attended 4 interactive meetings held at monthly intervals. The targets of the course were: 1) to identify sources of CHO, fats and proteins; 2) to count CHO and to split them among meals; 3) to assume CHO-rich foods without changing daily calorie or carbohydrate intake; 4) to modify the diet so as to correct hypoglycaemic events. To evaluate the effect of the course, patients completed a 7-day food record and answered a questionnaire covering the targets of the course at baseline, at the end of the course and 7 months later. After the course dietary knowledge improved significantly. The number of patients who weighed foods, estimated CHO food content and correctly distributed CHO among meals also increased. After the course patients reacted better when faced with hypoglycaemia. The knowledge acquired persisted 7 months after the end of the course. Therefore, we conclude that a simple teaching program can improve diet knowledge in Type 1 diabetics and establish a sustained habit of counting CHO.