Despite numerous profiling studies that report differential miRNA expression in pancreatic ductal adenocarcinoma (PDAC), it remains unclear what, if any, role miRNAs play during PDAC initiation and/or progression. This study was undertaken to examine the function of three pancreas enriched miRNAs towards the development of PDAC. Studies in mice over the past decade have shown that PDAC arises following transdifferentiation of the pancreatic acini into ductal like cells, i.e. the process of acinar ductal metaplasia or ADM. In the context of mutant Kras, ADM gives rise to PanINs which are followed by invasive PDAC. The molecular events describing ADM are still under active investigation. We hypothesize that miR-216a, -216b and -217 maintain the acinar phenotype and upon their loss induce ADM, PanINs and PDAC. CRISPR/CAS genome editing was used to generate the three germline miRNA knockout mice (miR-216a, -216b and -217). To assess a phenotype of the knockouts, mice were challenged with the cholecystokinin analog careulein or crossed with mice harboring Kras conditionally activated in the pancreas. Validation of the knockouts was performed by DNA sequencing and qRT-PCR. An in vitro ADM assay was performed by culturing pancreatic acinar cells on collagen/TGFα. Increased in vitro acinar-ductal transdifferentiation was observed when the isolated acinar cells from the miRNA knockouts are cultured on collagen. Increased apoptosis and duct formation was evident when the knockout mice were subjected to caerulein induced acute pancreatitis. miRNA-216a and miR-216b knockout mice were also found to develop pancreatic duct glands following careulein injection. The bigenic offspring of miRNA knockout and EL-KrasG12D cross dramatically accelerates the development of Kras driven acinar-ductal metaplasia and formation of PDA precursor lesions. These results suggest that miRNA-216/217 is required for maintaining the acinar fate and for regeneration following pancreatic injury. We propose that these miRNAs act as tumor suppressors by repressing ductal metaplasia and thereby limit the extent of PDAC progression.