We conducted a pilot trial of a new mobile and web-based intervention to improve diabetes adherence. The text messaging system was designed to motivate and remind adolescents about diabetes self-care tasks. Text messages were tailored according to individually-reported barriers to diabetes self-care. A total of 23 adolescents with type 1 diabetes used the system for a period of three months. On average, they received 10 text messages per week (range 8-12). A matched historical control group from the same clinic was used for comparison. After three months, system users rated the content, usability and experiences with the system, which were very favourable. Comparison of the intervention and control groups indicated a significant interaction between group and time. Both groups had similar HbA(1c) levels at baseline. After three months, the mean HbA(1c) level in the intervention group was unchanged (8.8%), but the mean level in the control group was significantly higher (9.9%), P = 0.006. The results demonstrate the feasibility of the messaging system, user acceptance and a promising effect on glycaemic control. Integrating this type of messaging system with online educational programming could prove to be beneficial.