Two male patients with pulmonary manifestations of Wegener's granulomatosis are presented. One had an elevated rheumatoid factor, and both had elevated levels of immunoglobulin E. Both demonstrated characteristic necrotizing granulomatous lesions on light microscopy of lung tissue. Immunohistologic analysis of lung tissue demonstrated a granular deposition of immunoglobulin G and complement. Raji cell assay of sera demonstrated elevated levels of circulating immune complexes in the sera of the one patient tested prior to any therapy. These findings support the hypothesis that immune complex deposition contributes to the pathogenesis of Wegener's granulomatosis.