The centrosome plays an important role in microtubule nucleation and organization, ensuring the establishment of cell polarity and balanced chromosome segregation. Recent studies have suggested that the loss of cell polarity and/or chromosome missegregation (aneuploidy) in human malignant tumors could result from defects in centrosome function. Using immunofluorescence analysis with an antibody to γ-tubulin (a well- characterized centrosomal component), we examined surgically resected human pancreatic tissues for centrosome abnormalities. The tissues included ductal carcinomas (n = 13), adenomas (n = 3), endocrine tumors (n = 3), chronic pancreatitis (n = 5), and normal pancreatic tissues (n = 12). We found that most (85%) carcinomas and some adenomas displayed abnormal centrosome profiles, characterized by an increase in size and number of centrosomes, and by their irregular distribution. In contrast, none of normal ductal and stromal tissues showed these abnormalities. These findings suggest that centrosome abnormalities may develop at a relatively early stage of pancreatic ductal carcinogenesis.