The systolic (sBP), diastolic (dBP) and mean (mBP) blood pressure were measured in hospitalized geriatric patients with (n = 30) and without (n = 100) pressure sores. A more intensive investigation was carried out in 18 elderly hospitalized geriatric patients without pressure sores, who were compared with 10 healthy young and 10 healthy elderly subjects. In these groups, the blood pressure was compared to the skin blood cell flux (SBF) as evaluated by the laser Doppler technique, at rest and during the post-occlusive reactive hyperaemia (PRH) response in the sacral area which is a high risk area for pressure sores. The patients with pressure sores had a significantly lower sBP (130 +/- 17 mmHg) compared to patients without pressure sores (140 +/- 20 mmHg). A significant correlation between a low resting SBF and a low mBP was found in all groups. An impaired PRH response corresponded to a low sBP in the two elderly groups. No correlation to dBP was seen at all. It is concluded that low mBP and sBP in elderly hospitalized patients were significantly correlated to a low resting SBF and a impaired reactivity of the skin microcirculation, respectively, and a low sBP was associated with pressure sores. Measurements of the systemic BP are of importance when classifying patients at risk of pressure sores.