When Irvin Fatt wrote his classical paper on pore-network modeling (Fatt 1956), he would probably not have thought that this field would become one of the largest fields of research in the porous media discipline. Pore-scale modeling has found its way as an expanding field of research for understanding the physics of flow and transport in porous media. In addition, it is becoming a valuable tool for prediction of petrophysical properties as part of the so-called Digital Rock Physics approaches, thus supplementing and replacing expensive and time consuming laboratory experiments. The recent popularity of pore-level modeling can also be attributed to advances in visualization of the pore space, to very high image resolution, and to the steady increase in computing power. This has made it possible to deal with a multitude of processes in the pore space and interactions with the solid phase (van Dijke and Piri 2007). The focus of this special issue of Transport in Porous Media is to provide an overview of some recent developments of various techniques for pore-scale modeling of multiphase flow and reactive transport.