Abstract: Nuclear factor kB (NF kB) is a transcriptional factor. It can regulate a battery of genes that are critical to innate and adaptive immunity, cell proliferation, inflammation, and tumor growth. MicroRNAs (miRNAs) are the short RNA molecules of 20-25 nucleotides in length that negatively regulate the gene expression in animals and plants primarily by targeting 3' untranslated regions of mRNAs. In this work, the authors reviewed the convergence of miRNAs and NF-kB signaling and dysregulation of miRNAs, and NF-kB activation in human diseases, particularly in cancers. The function of miR-146, miR-155, miR-181b, miR-21, and miR-301a in NF-kB activation and their impact on tumorigenesis are discussed. To decipher the biological function and pathological contribution of the factors and target genes in NF-kB dysregulation is essential to analyze the complexity of immune systems and to develop therapeutics against cancer.