A 49-year-old woman had three distinct episodes of pulmonary hemorrhage over a 11-year period separated by symptom-free intervals of 6 and 5 years. The first and third episodes were associated with mild glomerulonephritis and linear deposition of IgG along glomerular/tubular basement membranes. The first episode was associated with a rising influenza A2 titer. Investigation of the third episode revealed circulating antiglomerular basement membrane antibodies detected by radioimmunoassay but not by indirect immunofluorescence. Antilung basement membrane antibodies were detected by both direct and indirect immunofluorescence. Recovery from each hemorrhage followed blood transfusion and oxygen therapy. This case demonstrates that (1) Goodpasture's syndrome, predominantly manifest by pulmonary hemorrhage, may have circulating antibodies with greater affinity for lung membrane compared with glomerular basement membrane, and (2) the antiglomerular basement membrane antibody response is not necessarily an acute self-limited event but may be a chronic or recurrent phenomenon.