Circular RNAs (circRNAs) are a novel class of highly stable noncoding RNAs that play significant biological roles in the regulation of many cellular processes including proliferation, apoptosis, angiogenesis and cell cycle progression. CircRNAs belong to a diverse class of stable RNAs expressed in most species and cell types and are highly tissue specific. Their high stability and tissue-specific expression makes them ideal biomarkers for disease. Indeed, their differential expression is well described in various diseases including several cancers, cardiovascular disease, diabetes and neurological disorders. However, their specific role in associated molecular pathways is yet to be properly determined. Furthermore, although studies demonstrate the potential of blood circRNAs as biomarkers in several diseases, the challenge remains to identify consistent and reproducible data across independent studies. Whilst the high stability and lower immunogenicity of circRNAs make them advantageous over traditional mRNA as an RNA therapeutic, more work is needed to develop efficient, cost-effective production systems that support scalable, commercial circRNA development.