This study aimed to determine the safety and efficacy of allogeneic mesenchymal stem cells transplantation (MSCT) in refractory rheumatoid arthritis (RA). Four patients with persistently active RA underwent MSCT. The outcome was evaluated by changes in the visual analog scale (VAS 100 mm) pain score, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), and 28-joint disease activity score (DAS-28). Three of four patients received a reduction in ESR, DAS-28, and pain VAS score at 1 and 6 months after transplantation. Two of the three had a European League Against Rheumatism (EULAR) moderate response at 6 months but experienced a relapse at 7 and 23 months, respectively. Two patients had no EULAR response to MSCT. No one had achieved the DAS-28-defined remission in the follow-up period. No serious adverse events were reported. Allogeneic MSCT is a safe treatment in severe and resistant RA, but the effectiveness needs to be clarified.