The aim of this review was to summarise and critically evaluate the evidence from randomised clinical trials (RCTs) of moxibustion as a treatment for patients with osteoarthritis (OA). Twelve databases were searched from their inception through July 2011. RCTs were considered whether they assessed any type of clinical outcome from moxibustion therapy for patients with OA localised to any joints. Two reviewers independently performed the selection of studies, data abstraction and validations. The risk of bias was assessed using the Cochrane criteria. Eight RCTs met our inclusion criteria, and most of them had significant methodological weaknesses. Six RCTs tested the effects of moxibustion against conventional oral drug therapies in patients with knee OA (KOA). Meta-analysis showed favourable effects of moxibustion on the response rate (n = 540; RR, 1.09; 95 % CI 1.03-1.17; P = 0.005; heterogeneity: χ(2) = 5.48, P = 0.36, I (2) = 9 %). Two RCTs tested the effects of moxibustion on response rate after 2 months. The meta-analysis failed to show favourable effects of moxibustion (n = 180; RR, 1.10; 95 % CI 0.97-1.24; P = 0.13; heterogeneity: χ(2) = 0.03, P = 0.87, I (2) = 0 %). In conclusion, consistent results show that moxibustion may be effective in symptom management in patients with KOA. However, because of the number of eligible RCTs and the high risk of bias in the assessment of the available RCTs, the evidence supporting this conclusion is limited.