A case of immunoblastic lymphadenopathy is presented. The patient's diagnosis was made from his clinical findings and lymph node pathology. Of particular note are long-standing pulmonary lesions of undetermined etiology and the exfoliation in sputum specimens of large numbers of immunoblasts identical to those seen in histologic sections of lymph node. Although other cases of immunoblastic lymphadenopathy with pulmonary findings have been published, 4, 5 only the histomorphology of these lesions has been described. This is the first reported case of immunoblastic lymphadenopathy with positive pulmonary cytology. Diagnosis of this condition requires histopathologic evaluation of diagnostic lymph nodes. Immunoblasts may be identified cytologically in sputum preparations and in this context are suggestive of but not diagnostic of this entity. The use of methyl green-pyronine stain to better differentiate immunoblasts is recommended.