Many biological processes, e.g. protein degradation by ATP dependent proteases and mitochondrial protein import, involve protein translocation through nanometer-sized pores. Recently, the transport of charged biopolymers driven electrophoretically across transmembrane pores has been studied at a single molecule level by a number of groups. In this talk I will describe some of our group's theoretical and computational efforts to understand the molecular mechanisms of protein translocation and unfolding inside pores. In particular, I will discuss how the translocation rate depends on the structure of the translocated proteins, protein-pore interactions, the pore dimensions and the magnitude of the driving force.