OBJECTIVES: To demonstrate the feasibility and patient acceptance of a health care intervention using the patient's mobile phone (HTA-Alert Study), and to describe the pattern of use of this tool in the usual clinical practice (INFONET Program) in hypertensive (HT) patients. METHODS: 1) HTA-Alert Study: 20 primary care investigators were randomized to Control (CG) or Intervention (IG) group. Investigators of IG registered their patients in a free SMS service. These patients received two short-messages per week, during 24 weeks. Messages addressed issues related with compliance and health habits. 2) INFONET Program: 40 Hypertension Units (UHTA) asked patients to enter periodically blood pressure into a private web site, where physicians had access to data. Physicians were asked to send free-text SMSs to the patient mobile phone via web application at their own convenience. RESULTS: 1) HTA-Alert: 33 Patients CG and 34 IG were studied. There was a relevant reduction in weight (from 80,47±9,76 kg to 76,84±8,92; p<0,001) in the IG. Hypertension was reduced in both groups, but IG patients showed an earlier control (61,8% control in IG vs 36,4% in CG at 12 weeks; p=0,038). 2) INFONET Program: The first 250 SMS were analysed. Percentages of SMS sent by physicians were: support (50.3%), Therapeutic compliance (2.7%), Asking for data (29.5%), Scheduling visits to surgery (6.0%), Modifying medication (1.6%), Others (9.9%). The most frequent scheduling was one SMS every 12 days. CONCLUSIONS: In the usual practice (INFONET Program), physicians use the SMS system in a different way than predicted (HTA-Alert). They tend to give support and to ask for data, instead of addressing compliance and life-habits messages. Frequency of messages was also lower. The use of SMSs seems to be a useful tool for educational programs, and it would be convenient to explore in more detail its effectiveness in health outcomes.