There have been few reports of flow cytometric studies of pancreatic neoplasms, whether endocrine or exocrine. In this report, the DNA content of three mucinous and seven serous cystic tumors of the pancreas was evaluated by flow cytometry on formaldehyde solution-fixed, paraffin-embedded tissue. Two serous cystadenomas were aneuploid, with the remaining five serous and all three mucinous being diploid. All cases had a low S phase (ranging from 0.1% to 3.1%), indicating neoplasms with a low turnover. From these results, it appeared that DNA flow cytometry as an independent factor did not discriminate between the benign pancreatic serous cystadenomas and the more aggressive mucinous cystic neoplasms.