The deregulation of microRNAs expression and activity is frequently observed in a wide variety of human pathologies including cancer. Accordingly, growing evidence indicates that the targeting of microRNAs biogenesis and pathways is emerging as a central tool for the development of novel RNA-based drugs and therapies to defeat diseases in humans. In this review we describe the various strategies that can be used to target microRNAs and specific RNA-binding proteins, involved in the regulation of their production, localization, stability and activity, in human cancer and cardiovascular diseases. We also focus on the efforts that are currently made to enhance the potency and stability of these therapeutic agents and their delivery to modulate in vivo microRNAs pathways. Finally, we present structural data on proteins that belong to the microRNA pathway for small molecules-based target therapy design.