This study aimed to investigate the effect of inpatient vs outpatient spa therapy on pain, quality of life, and anxiety in elderly patients with generalized osteoarthritis. A total of 150 patients were randomized into three groups. Group I was given medical treatment, group II was treated as outpatients, and group III was treated as inpatient spa therapy. Assessments were made using the Pain (VAS), EQ-5D-3L Scale, and State and Trait Anxiety Inventory (STAI) at the beginning of treatment (W0), at the end of treatment (W2), and at the fourth week after treatment (W6). The comparison of outpatient spa group and etodolac treatment group showed that outpatient spa group was superior to etodolac treatment group in all evaluated parameters at W2 vs W0 and W6 vs W0. The comparison of inpatient spa group and etodolac treatment group showed that inpatient spa group was superior to etodolac treatment group in all evaluated parameters at W2 vs W0 and W6 vs W0. The comparison of inpatient spa group and outpatient spa group showed that inpatient spa group was superior to outpatient spa group in all evaluated parameters except STAI-TXII at W2 vs W0 and in all evaluated parameters W6 vs W0. Spa therapy, either as an outpatient or inpatient basis, may have a positive effect on pain, anxiety, and quality of life in geriatric patients with generalized osteoarthritis. The inpatient spa therapy may be more beneficial than outpatient spa therapy. When the side effects of drug treatments are emphasized, spa therapy may be considered as an interesting option for elderly with osteoarthritis.