Our previous crossover randomized trial suggested that spa therapy added to usual pharmacotherapy provides benefits that lasted 6 months over pharmacotherapy alone in rheumatoid arthritis patients. We now extend, and report the long-term results of that study. In the crossover trial, patients were randomized to spa therapy first group or control first group (first assignment, period 1, 6 months); after this period and washout phase (9 months), they crossed over to the other arm (second assignment, period 2, 6 months). In this long-term study, we now analyze the 15-month results of the first assignment, and 12-month results of the second assignment in the opposite side with a 6-month extension of the follow-up period. The clinical outcome measures were pain, patient and physician global assessment, Health Assessment Questionnaire, and Disease Activity Score-28. The 15-month results of first assignment revealed no statistically significant differences between the groups in any of the efficacy outcomes (p > 0.05 for all). The 12-month results for the second assignment after crossover revealed a statistically significant decrease between the groups regarding the patient global assessment scores (p = 0.016), physician global assessment scores (p = 0.003) and swollen joints counts (p = 0.030); however, no statistically significant difference was found between the groups in any of the other efficacy outcomes (p > 0.05 for all). The short- and medium-term beneficial effects of the 2-week spa therapy added to the usual pharmacotherapy observed through the initial 6-month evaluation period may be maintained mildly to moderately to the 12-month mark in rheumatoid arthritis patients receiving conventional disease-modifying antirheumatic drugs. Further studies with a larger sample size are needed for the confirmation of the study results.