The prevalence of infectious disease in patients with rheumatoid arthritis (RA) is high. Infection causes problems in RA treatment and also affects prognosis. In this study, we examined the clinical characteristics of patients with RA who required hospitalization for infection at our hospital. Between April 2007 and March 2012, there were 79 patients with RA (64 women, 15 men) who had at least one infection requiring hospitalization. Infection most commonly occurred in the upper respiratory tract and pulmonary system (52.3%), urinary tract (11.9%), and skin and connective tissue (11.0%). Compared with the control group (noninfected outpatients with RA), the infection group had a significantly higher incidence of hypoalbuminemia (p < 0.001). Because hypoalbuminemia was already present before infection in the infection group, it can be inferred that hypoalbuminemia is associated with occurrence of infection in patients with RA. Twenty patients had a recurrent infection (comprising a total of 42 infective episodes), while the other 59 had a single infection. Interstitial lung disease (p = 0.029) and daily prednisolone use (p = 0.046) were significantly more common in the recurrent infection group than in the single infection group. These results suggest that hypoalbuminemia, interstitial lung disease, and daily prednisolone use are worth paying attention to with regard to development of infection during RA treatment.