Circular RNAs (circRNAs) are a class of abundant and conserved RNAs in animals and plants . Most circRNAs are produced from a special type of alternative splicing known as back-splicing, and are predominantly localized in cytoplasm . However, the general function of circRNA in vivo is still an open question. Several circRNAs have known functions including sequestration of miRNAs or RNA binding proteins (RBPs) (i.e., as competitors of the linear mRNAs), and modulation of transcription and interference with splicing . Nevertheless, the function of the remaining circRNAs is an uncharted territory and has not benefitted as much from the advancement in sequencing technology until lately. Since in vitro synthesized circRNAs can be translated in cap-independent fashion and many protein-coding genes in higher eukaryotes can produce circRNAs through back-splicing of exons, it is highly possible that they function as mRNAs in vivo to direct protein synthesis. Recent studies indicated that some cytoplasmic circRNAs can be effectively translated into detectable peptides, and many short sequences, including m6A modification sites have been suggested to function as IRES-like elements to drive circRNA translation . Using various direct and indirect evidences that support circRNA translation, we conducted an integrative analysis to predict the potential of all circRNAs in coding for functional peptides. The result of such prediction and the supporting evidences were summarized in the TransCirc database.