Background Evidence for non-pharmacological interventions in hand osteoarthritis is promising but still scarce. Combined interventions are most likely to best cover the clinical needs of patients with hand osteoarthritis (OA). The aim of this study was to evaluate the effect of a combined, interdisciplinary intervention feasible in both primary and specialist care compared to routine care plus placebo in patients with hand OA. Methods This was a randomised, controlled 2-month trial with a blinded assessor. In the combined-intervention group, rheumatology-trained health professionals from different disciplines delivered a one-session individual intervention with detailed information on functioning, activities of daily living, physical activity, nutrition, assistive devices, instructions on pain management and exercises. Telephone follow up was performed after 4 weeks. The primary outcome was grip strength after 8 weeks. Secondary outcomes were self-reported pain, satisfaction with treatment, health status, two of the Jebsen-Taylor Hand Function subtests and the total score of the Australian/Canadian Hand Osteoarthritis Index (AUSCAN). Statistical significance was calculated by Student’s t test or the Mann-Whitney U test depending on data distribution. Binominal logistic regression models were fitted, with the primary outcome being the dependent and the group allocation being the independent variable. Results There were 151 participating patients (74 in the combined-intervention and 77 in the routine-care-plus-placebo group) with 2-month follow-up attendance of 84% (n = 128). Grip strength significantly increased in the combined-intervention group and decreased in the routine-care group (dominant hand, mean 0.03 bar (SD 0.11) versus − 0.03 (SD 0.13), p value = 0.001, baseline corrected values) after 8 weeks. Conclusion The combined one-session individual intervention significantly improved grip strength and self-reported satisfaction with treatment in patients with hand OA. It can be delivered by different rheumatology-trained health professionals and is thus also feasible in primary care. Trial registration ISRCTN registry, ISRCTN62513257 . Registered on 17 May 2012.