Our work demonstrates that miR‐21 can confer drug resistance to 5‐FU in pancreatic cancer cells by regulating the expression of tumor suppressor genes, as the target genes of miR‐21, PTEN and PDCD4 can rescue 5‐FU sensitivity and the phenotypic characteristics disrupted by miR‐21. The gene discussed is PDCD4; the disease is pancreatic neoplasm.