Flow cytometric analysis of nuclear DNA content was performed in 26 adenoid cystic carcinomas of the submandibular gland using archived, paraffin-embedded tissues. The DNA content was compared with multiple histologic parameters and clinical course. Ten carcinomas (38%) were aneuploid and 16 (62%) diploid. Aneuploid carcinomas demonstrated a higher frequency of solid cytoarchitecture, lymph node metastases, and advanced clinical stage, as compared with diploid carcinomas. Other histologic features predicting aggressive clinical behavior also correlated with abnormal DNA content and included invasion of nerves larger than 0.25 mm and intravascular extension. Our data suggest that DNA content analysis can be an effective objective parameter in the clinicopathologic assessment of adenoid cystic carcinoma.