MicroRNA-133a has been proven downregulated in many human malignancies and correlated with tumor progression. However, the roles of miR-133a and its related molecular mechanisms in pancreatic cancer are still not clear. Here we found that miR-133a expression was significantly downregulated in pancreatic cancer tissue samples and cell lines by using quantitative real-time RT-PCR. Decreased miR-133a expression was significantly correlated with aggressive clinicopathological features and poor survival. In addition, miR-133a was identified to be a tumor suppressor, as transfection of miR-133a mimics in PANC-1 cells was able to reduce cell proliferation, invasion, and migration and promote cell apoptosis in vitro and suppress tumorigenicity in vivo. Further, we observed an obvious inverse correlation between FSCN1 and miR-133a levels in tumor samples, and FSCN1 was confirmed as a direct target of miR-133a by using Luciferase Reporter Assay. These findings suggest an important role of miR-133a in the molecular etiology of cancer and implicate its potential application in gene therapy of pancreatic cancer.