To evaluate the additional effect and safety of peloidotherapy to usual care at short- and middle-term in patients with rheumatoid arthritis (RA). RA patients were recruited in the medical ecology and hydroclimatology department of Istanbul Medical Faculty and were randomized into two parallel groups. Peloidotherapy group was treated with heated mudpack (41-42 °C) on painful and active joints (5 days/week, during 2 weeks) + usual care. Control group received usual care alone. Randomization was performed by using a computer-generated table of random numbers and was blinded. The sequence was concealed until interventions were assigned. The investigator was blinded. The assessments were done before and after the intervention, 1 month and 3 months after the completion of treatment. The main criterion was the number of patients with low disease activity (DAS 28 ≤ 3.2) at the end of follow-up. Other judgment criteria were pain (VAS), patient's global assessment (VAS), physician's global assessment (VAS), Health Assessment Questionnaire (HAQ), Disease Activity Score (DAS 28), CRP, and ESR. Fifty-six patients were recruited and analyzed: 29 in peloidotherapy group and 27 in the control group between 11/2011 and 02/2012. At the third month, 9/29 patients were with low disease activity in peloidotherapy group and 4/27 in the control group (p = 0.15). There was a statistically significant improvement in favor of peloidotherapy group for HAQ during all follow-up period (0.25 vs 0.63, p = 0.007 at the end of the treatment, 0.29 vs 0.68 p = 0.007 at the 1st month and 0.30 vs 0.59, p = 0.040 at the 3^rd month). Pain (35vs50, p = 0.028), patient's global assessment (37vs53, p = 0.028), physician's global assessment (33vs48, p = 0.030), and DAS28 (3.76vs4.58, p = 0.049) improved significantly more in peloidotherapy group at the 3^rd month. There were no between group differences for ESR and CRP. There were no important adverse events. There is no significant improvement for the main criteria so we can't conclude that peloidotherapy has additional effect over usual care. But most of the other judgment criteria improved more in the peloidotherapy group than in the control group and peloidotherapy was well tolerated. A trial with higher statistical power is necessary to if we want to reveal the effects on disease activity and confirm the short and middle term efficiency of this treatment modality on pain and quality of life.