Telemonitoring of home blood pressure measurements (TBPM) is a new and promising supplement to diagnosis, control and treatment of hypertension. We wanted to compare the outcome of antihypertensive treatment based on TBPM and conventional monitoring of blood pressure. Participants were recruited from a prevalence study among citizens aged 55-64 years in the municipality of Holstebro, Denmark. The study was a randomized, controlled, unblinded 3 months' trial. In the intervention group, antihypertensive treatment was based on TBPM with transmission of the measurements and subsequent communication by telephone or e-mail. In the control group, patients received usual care. Primary outcome was reduction in daytime ambulatory blood pressure measurements (ABPM) from baseline to 3 months' follow-up. Of 375 participants randomized, primary outcome data were available for 356 (95%). In both groups, daytime ABPM decreased significantly. The decrease in daytime ABPM in the intervention group was systolic/diastolic, - 8 ± 12/ - 4 ± 7 mm Hg. This did not differ significantly from the control group's - 8 ± 13/- 4 ± 8 mm Hg. An equal number of participants obtained normal daytime ABPM, in the intervention group 17% (31/175) versus control 21% (37/181), P = 0.34. We found that both TBPM patients and controls achieved a significant blood pressure reduction in this randomized, controlled, unblinded 3-month trial. We found no difference in blood pressure reduction or number of patients reaching blood pressure goals. Further information and education of some general practitioners seem to be relevant regarding blood pressure management and control of hypertension.