Sufficient antihypertensive treatment compliance is one of the key factors determining its effectivity. The objective of randomised, non-interventional clinical study COAST with telmisartan in the dose 40 or 80 mg daily was not only to demonstrate efficacy and safety of the treatment, but to evaluate influence of electronic monitoring device Helping Hand (HH) on compliance to treatment and to improve its efficacy. There were in cross-over designed study randomised into group A 349 patients (at first treated 6 months with telmisartan with use of HH, followed by next 6 months therapy without use of HH) and to group B 178 patients (at first treatment without HH, after 6 months until the end of 12th month with HH). There were observed in both study groups statistically significant decrease of systolic and diastolic blood pressure (no statistically significant difference between both groups). Use of HH improved compliance in 63 % of them (p = NS), and at the same time compliance improved significantly more in the group B like in the group A (73,6 % vs 56,0 %; p < 0,001). Telmisartan treatment in both groups was very well tolerated and safe (not significant changes between groups A and B). Adverse effects were very rare and mild.