BACKGROUND Supporting self-management intends to improve life-style, which is beneficial for patients with mild osteoarthritis (OA). We evaluated a nurse-based intervention on older OA patients' self-management with the aim to assess its effects on mobility and functioning. METHODS Randomized controlled trial of patients (> or = 65 years) with mild hip or knee OA from nine family practices in the Netherlands. Intervention consisted of supporting patients' self-management of OA symptoms using a practice-based nurse. Outcome measures were patients' mobility, using the Timed Up and Go test (TUG), and patient reported functioning, using an arthritis specific scale (Dutch AIMS2 SF). RESULTS Fifty-one patients were randomized to the intervention group and 53 to the control group. Patient-reported functioning improved on four scales in the intervention group compared to one scale in the control group. However, this result was not significant. Mobility improved in both groups, without a significant difference between the two groups. There were no differences between the groups regarding consultations with family physicians or physiotherapists, or medication use. CONCLUSION A nurse-based intervention on older OA patients' self-management did not improve self-reported functioning, mobility or patients' use of health care resources. ; The Netherlands Organisation for Health Research and Development funded this study (ZonMW, number 920-03-252).