The aims of the study were to evaluate the reproducibility of quantitative ultrasound (QUS) densitometry of the hands and to verify whether this method is sensitive to phalangeal bone changes occurring in osteoarthritis patients and in erosive osteoarthritis patients. We studied 60 postmenopausal women (aged 63.8 +/- 3.2): 20 had osteoarthritis, 20 had erosive osteoarthritis, 20 were postmenopausal without local pathology of the hand and eight were premenopausal (aged 23.5 +/- 3.4). The patients were evaluated by means of a DBM Sonic 1200 which is able to evaluate ultrasound transmission velocity (amplitude-dependent speed of sound). The results indicated good intra- and interoperator reproducibility (coefficient of variation = 0.99% and 1.04%) in the premenopausal group. The ultrasound device was able to discriminate between the different groups and detected differences between the QUS values of erosive osteoarthritis patients, osteoarthritis patients and control subjects. QUS densitometry is reproducible and sensitive to bone changes occurring in patients with osteoarthritis and as well as in those with erosive osteoarthritis.