Home measurement of blood pressure (BP) can improve compliance. The aim of this study was to evaluate if the efficacy of losartan in hypertension could be enhanced by providing patients with a device for home BP measurement. In this open, randomised, prospective, multi-centre study in 244 Swiss practices, patients with mild-to-moderate hypertension were randomised to a group receiving a home BP measuring device (OMRON) (group 2), or to a group where this device was not provided (group 1). After 8 weeks of treatment with losartan, the responder rates between subjects performing home measurement of BP were compared with those without self-measurement, whereby exclusively sphygmomanometric office BP values were considered. A total of 622 subjects completed the study. Treatment with losartan significantly reduced diastolic (DBP) and systolic BP (SBP) (P < 0.0001). Overall, the group with home BP measurement showed an increased responder rate (DBP < or =90 mm Hg) by 6.4% (59.8% vs 66.2%; 0.05 < P < 0.1). This difference was mainly due to female patients (64.1% vs 73.2%), where it reached statistical significance (P < 0.01). Pretreated patients showed a 9.0% improvement of response in the home measurement group as well (0.05 < P < 0.1). The responder rate in newly treated subjects was relatively high, reaching 79.5% (DBP < or =90 mm Hg or reduction > or =10 mm Hg DBP from baseline). However, home measurement did not significantly improve BP control in these new patients (81.4% vs 77.7%). Overall, home measurement can lead to a slight improvement of BP control. This improvement was most evident in females, reaching significance.