Background. Some chronic diseases have been associated to an impairment of nutritional status. Objective. To analyze nutritional status and its relation to dietary intake, disease activity and treatment in rheumatoid arthritis. Patients and methods. We have included 93 patients (43 men and 50 women) and 93 age- and sex-matched healthy controls. The assessment of nutritional status included anthropometric (body mass index, tricipital skin fold and midarm muscular circumference) and biochemical (serum albumin, prealbumin and retinol binding protein) parameters. Dietary intake was calculated from a food frequency questionnaire. As a measure of disease activity, we used the Health Assessment Questionnaire, Ritchie index, tender and swollen joint count and C-reactive protein. Statistical analysis was performed in the whole series and in every functional class. Results. In the whole series, midarm muscular circumference and serum albumin were significantly lower in patients than in controls. All anthropometric parameters and serum albumin were significantly lower in patients in functional class IV than in their respective controls. The dietary intake of energy, carbohydrates, vegetal proteins and lipids was higher in patients than in controls. Midarm muscular circumference and serum albumin had a significant inverse relation with disease activity parameters; body mass index, midarm muscular circumference and serum albumin correlated inversely with the cumulative dose of glucocorticoids. Conclusions. Patients with rheumatoid arthritis in functional class IV have an impairment of nutritional status without a deficient dietary intake. The differences found in other functional classes are explained by rheumatoid arthritis itself. Nutritional parameters are related to disease activity and glucocorticoid treatment.