Medical education of hypertensives as well as of other asymptomatic cardiovascular risk patients requires individualized, interactive and attractive strategies. Electronic teaching set up in hospital or clinic settings opens the way of the future, saving time and allowing more advantageous use of caretakers. ISIS (Initiation Sanitaire Informatisee et Scenarisee), a French computer assisted program for cardiovascular risk patients, combines a scientific information, divided in 12 sequential but independent modules, with a recreative imaginary trip in the world of ancient Egypt. To test the impact of this tool on patient health information retention, 158 hypertensives hospitalized in a day-hospital clinic were randomized into an intervention or ISIS group (IG, n = 79) and a control group (CG, n = 79). Both groups received cardiovascular education through standard means. In addition, IG patients underwent a 30 to 60 min session on the computer. Cardiovascular knowledge was tested by a nurse administering a standardized 28-item questionnaire before and two months after education. Retesting was done by telephone interview. A total of 138 completed questionnaires (69 from each group) were analyzed. Overall mean cardiovascular knowledge score before education (14.3 +/- 4.2, range 4-25) improved significantly after education (3.7 +/- 3.5, p = 0.0001). This improvement was more important in the IG than the CG (3.8 +/- 3.6 vs 2.4 +/- 3.2 respectively, p = 0.02), especially in hypertensives having a known disease for more than six months. Isis is now available in two languages: French and English. Patients' satisfaction and the conclusion of this comparative trial encourage confirmation of these first results in other French or English speaking populations, in order to test the long term effects of structured electronic teaching sessions on health behaviour, and to promote a wide use of computers and multimedia communication in hypertension control programs.