We have sometimes encountered invasive ductal carcinomas (IDCs) of the pancreas containing intraductal carcinoma components in the intra- and / or extra-tumor area. The purpose of this study was to investigate whether intraductal carcinoma components would be useful for predicting the outcome of IDC patients. Forty-seven surgically treated IDCs were examined, and all histological tumor sections were stained with Elastica to accurately confirm intraductal carcinoma components. Well-known clinicopathological parameters that exhibited a significant correlation in the univariate analyses for predicting disease-free survival (DFS) and overall survival (OS) were entered into the Cox proportional hazard multivariate analysis. Since the lowest P-value predicting DFS or OS periods was observed in IDCs with more than 10% intraductal carcinoma components and those with 10% or less intraductal carcinoma components (P = 0.028 and P = 0.019), we established the cutoff value of intraductal carcinoma components at 10%. In the multivariate analyses for DFS and OS, the presence of more than 10% intraductal carcinoma components showed a marginally significant increase in the hazard rate (HR) of tumor recurrence (P = 0.067) and significantly increased the HR of mortality (P = 0.040). The present study demonstrated that IDCs with more than 10% intraductal carcinoma components were associated with a significantly better patient outcome than those with 10% or less intraductal carcinoma components.