To study the association of malnutrition with nosocomial infection in a general medical and surgical inpatient population, we retrospectively compared 45 patients with nosocomial infection to 45 uninfected control patients, matched using several nonnutritional variables known to predispose to nosocomial infection. Univariate and multivariate analyses were done. Poor nutritional score (derived from serum albumin, total lymphocyte count, and unintentional body weight loss), unintentional body weight loss, low serum albumin level at both time of admission and the first nosocomial infection, and worsening in the nutritional score and serum albumin from admission to the first nosocomial infection were associated with the development of nosocomial infection. Nutritional factors were more abnormal in subgroups of patients with nosocomial pneumonia, urinary tract infection, wound infection, and bacteremia than in controls. The findings suggest that further study of correlations between nutritional factors and nosocomial infections is needed.