Here, we report that Sbp1 inhibits translation of the mRNA that encodes polyadenosine [poly(A)]-binding protein Pab1 in an RNA- and RGG-dependent manner in vitro. We further elucidate the molecular interactions that are important for the translational regulation. Pab1 is an essential regulator of mRNA metabolism in eukaryotes, including splicing (Jenal et al. 2012), 3′ end processing (Jenal et al. 2012), and mRNA export (Bresson and Conrad 2013), localization (Vazquez-Pianzola et al. 2011), translation (Munroe and Jacobson 1990; Tarun and Sachs 1996; Tarun et al. 1997; Wells et al. 1998), and degradation (Bresson and Conrad 2013). Pab1 not only binds to the 3′ poly(A) tail and other adenosine-rich (A-rich) regions of cellular mRNAs (Gilbert et al. 2007), but also directly interacts with the eukaryotic mRNA cap-binding complex via binding with its component, eIF4G (Tarun and Sachs 1996; Tarun et al. 1997; Wells et al. 1998). In addition to stimulating mRNA translation in general, Pab1 inhibits the decapping of mRNAs in the cell (Coller and Parker 2004; Parker 2012). As expected, expression of Pab1 is tightly regulated. In this study, we demonstrate that the two RRM domains of Sbp1 bind specifically to the A-rich region in the 5′UTR of Pab1 (5′UTRPab1) and the RGG domain of Sbp1 directly interacts with Pab1. These molecular interactions explain at least in part how Sbp1 inhibits the translation initiation of Pab1 mRNA.