RNA aptamers are non-coding small RNAs that bind to their cognate targets with high specificity and affinity. They are generally identified by iterative rounds of in vitro selection termed SELEX (Systemic Evolution of Ligands by Exponential Enrichment). Similar to antibodies, they can inhibit, modulate and disrupt the functions of target proteins effectively, making them promising therapeutic agents for the treatment of various diseases and targeted drug delivery. Herein we summarize the recent progress of RNA aptamers as potential therapeutics, and highlight a few pioneer examples in the stage of both clinical trials and pre-clinical developments.