Pancreatic cancer (PC), highly malignant, is one of the most lethal cancers. Interferon-induced transmembrane protein 1 (IFITM1) has recently been regarded as a new molecular marker in human cancers. However, the role of IFITM1 in PC remains unclear. In this study, a short hairpin RNA (shRNA) was constructed to assess the effect of IFITM1 on PANC-1 and ASPC-1 cells. The level of IFITM1 was downregulated in cells transfected with shRNA targeting IFITM1 (sh-IFITM1). Silencing of IFITM1 significantly decreased cell viability, downregulated the level of Ki-67, arrested cell at G1/S phase, reduced the number of cells in S phase, and decreased cyclinD1, cyclinE, CDK2, and CDK4 levels. Moreover, Hoechst staining and Western blotting analysis showed that cell apoptosis was induced by IFITM1. IFITM1 knockdown suppressed the MAPK signaling pathway by downregulation of p-ERK, p-P38, and p-JNK levels. These findings suggested that IFITM1 could be considered a potential therapeutic target for PC.