The gastric brushings (GBRs) and endoscopic biopsies obtained concurrently from 27 patients in whom malignant lymphoma was diagnosed or suggested by either modality were assessed to evaluate the utility of cytologic examination in the diagnosis of gastric lymphoma. GBRs provided a definitive diagnosis of lymphoma in 2 (28%) of 7 patients with a prior history of lymphoma and 10 (56%) of 18 patients with primary gastric lymphoma, yielding an overall sensitivity of 48%. All the lymphomas diagnosed cytologically were large cell type. GBRs were suspicious for a malignant neoplasm in four lymphoma patients whose concurrent biopsies were negative. GBRs obtained from two patients who had gastritis were reported as suspicious for lymphoma. There were no false-positive diagnoses.