Patients with rheumatoid arthritis (RA) suffer from muscle loss, causing reduced muscle strength and endurance. The current study aimed to: (1) evaluate the effects of combined strength and endurance training (CT) on disease activity and functional ability in patients with RA and (2) investigate the benefits of a 6-month supervised CT program on muscle strength, cardio-respiratory fitness, and body composition of RA patients. Forty patients with RA, aged 41-73 years, were recruited for the current study. Twenty of these patients (19 females, one male) were randomly assigned to a 6-month supervised CT program; 20 patients (17 females, three males) served as controls. Within the CT program, strength training consisted of sets of weight bearing exercises for all major muscle groups. In addition to strength training, systematic endurance training was performed on a cycle ergometer two times per week. For RA patients involved in CT, disease activity (p = 0.06) and pain (p = 0.05) were reduced after the 6-month training period while general health (p = 0.04) and functional ability (p = 0.06) improved. Cardio-respiratory endurance was found to have improved significantly (by 10%) after 6 months of CT (p < 0.001). The overall strength of patients undertaking CT increased by an average of 14%. Lean body mass increased, and the percentage of body fat was found to decrease significantly (p < 0.05). A combination of strength and endurance training resulted in considerable improvements in RA patients' muscle strength and cardio-respiratory endurance, accompanied by positive changes in body composition and functional ability. Long-term training appears to be effective in reducing disease activity and associated pain and was found to have no deleterious effects.