The link between nonresolving inflammation and cancer is well documented. On the one hand, epidemiologic evidence supports that approximately 25% of all human cancer worldwide is caused by nonresolving inflammation. On the other hand, inflammatory cells are found in the microenvironment of most, if not all, tumors. In the tumor micro-environment, inflammatory cells and molecules influence almost every aspect of cancer. MicroRNAs (miRNAs) participate in the initiation and progression of nonresolving inflammation-related cancer by regulating the key genes and related signaling pathways. Further investigation into the molecular mechanisms by which miRNAs carry out their functions will be of great value in the prevention, early diagnosis, and treatment of tumors.