Poly(A)-specific ribonuclease (PARN) specifically catalyzes the degradation of the poly(A) tails of single-stranded mRNAs in a highly processive mode. PARN participates in diverse and important intracellular processes by act-ing as a regulator of mRNA stability and translational efficiency. In this article, the equilibrium unfolding of PARN was studied using both guani-dine hydrochloride and urea as chemical denaturants.