High-dependency units are of benefit to patients and to the associated intensive care unit. However, the effectiveness of high-dependency care has not been quantified. We studied 100 consecutive patients whose high-dependency unit admission was longer than 48 h. The Logistic Organ Dysfunction System was used to assess organ dysfunction on a daily basis in these patients. The median Logistic Organ Dysfunction System score on admission was 3. The mean duration of stay was 4.3 days, and the median Logistic Organ Dysfunction System score on day 4 was 1. Sixty-six per cent of patients had a lower Logistic Organ Dysfunction System score at discharge. In the remaining patients, the commonest reason for no change or a higher Logistic Organ Dysfunction System score was renal dysfunction. High-dependency care is effective in the majority of patients in terms of improved physiological status and most patients were discharged with minor physiological dysfunction. This level of physiological dysfunction could be applied as a discharge threshold. Poorer patient outcome is associated with increased age and a longer stay on the unit. This poor outcome was commonly due to renal system dysfunction, and invariably followed surgery.