Rheumatoid arthritis (RA) is a progressive articular disease. In addition to damaging the joints, it may cause multiple organ complications, and considerably impair the patient's functioning. Elderly patients with RA report pain, fatigue, mood disorders, sleep disorders and insomnia, accompanied by weakness, poor appetite, and weight loss. All these factors combined have an adverse effect on the patient's perceived quality of life (QoL). Due to the chronic nature of RA and the high risk of malnutrition in this patient group, the present study investigated QoL, activities of daily living, and frailty syndrome severity in relation to MNA (Mini Nutritional Assessment) questionnaire scores among elderly RA patients. The study included 98 patients (aged over 60) diagnosed with RA per the ARA (American Rheumatism Association) criteria. The following standardized instruments were used: WHOQoL-BREF for QoL, the Edmonton Frail Scale for frailty syndrome severity, MNA for nutritional status assessment, and MMSE (Mini-Mental State Examination) to assess any cognitive impairment. Medical data were obtained from hospital records. Patients with a different nutritional status differed significantly in terms of limitations in activities of daily living (ADL) and instrumental activities of daily living (IADL). Higher levels of malnutrition were associated with greater limitations in activity. An adverse impact of lower body weight on cognitive function was also observed (dementia was identified in 33.33% of malnourished patients vs. 1.79% in patients with a normal body weight). Likewise, frailty was more common in malnourished patients (mild frailty syndrome in 33.3%, moderate in 16.67%, and severe in 16.67%). Malnourished patients had significantly lower QoL scores in all WHOQoL-BREF questionnaire domains than those with a normal body weight, and multiple-factor analysis for the impact of selected variables on QoL in each domain demonstrated that frailty was a significant independent determinant of poorer QoL in all domains: perceived quality of life (β = -0.069), perceived health (β = -0.172), physical domain (β = -0.425), psychological domain (β = -0.432), social domain (β = -0.415), environmental domain (β = -0.317). Malnutrition was a significant independent determinant of QoL in the "perceived health" domain (β = -0.08). In addition, regression analysis demonstrated the positive impact of male sex on QoL scores in the psychological (β = 1.414) and environmental domains (β = 1.123). Malnourished patients have a lower QoL than those with a normal body weight. Malnutrition adversely affects daily functioning, cognitive function, and the severity of frailty syndrome. Frailty syndrome is a significant independent determinant of poorer QoL in all WHOQoL BREF domains.