The Hypertension and Diabetes Screening and Awareness (HYDRA) study is a cross-sectional point-prevalence study performed in September 2001; 45,125 primary care attendees were recruited from a representative nationwide sample of 1912 primary care practices in Germany. Around 42% of all patients presenting in these practices had hypertension (WHO definition). In approximately 70% of these patients, hypertension was diagnosed by doctors and 84% of diagnosed patients were on antihypertensive medication, but in less than 30% of treated patients was blood pressure controlled (< 140/90 mmHg). The control rate in all patients presenting with hypertension (including those patients unrecognized) was as low as 19%. The present analysis aimed to find explanations for this unsatisfactory outcome of hypertension control. The main finding was that the rate of diagnosis of hypertension is alarmingly low in young people, probably due to insufficient blood pressure screenings. The data further indicated that doctors still set their target of treatment according to outdated guidelines and that doctors still orientate their treatment primarily with regard to the diastolic pressure. These insights into the causes of unsatisfactory hypertension control may help to direct future educational programmes designed to improve hypertension management specifically to these deficits and thereby to improve control rates.