Measuring electron transfer rates as well as charge transport characteristics in DNA have produced a number of seemingly contradictory results, ranging from insulating behavior to the suggestion that DNA is an efficient medium for charge transport. Among other factors, environmental effects play a crucial role in determining the effectivity of charge propagation along the double helix. The chapter provides an in-depth overview of charge transfer theories and their implication for addressing the interaction of a molecular conductor with a dissipative environment. It focuses on the possible applications of these approaches for charge transport through DNA-based molecular wires. An overview of different approaches to address charge propagation in a dissipative environment is presented. Some results from the ab initio calculations of DNA oligomers in the presence of an aqueous environment are also provided. The chapter introduces basic facts on how to model the interaction between an arbitrary quantum mechanical system with a dissipative environment. A special application to a DNA model is also discussed. Focusing on individual factors affecting charge propagation helps to shed light onto the relevant mechanisms controlling the charge dynamics in DNA. The chapter addresses environmental effects in the charge transport through DNA oligomers within a minimal Hamiltonian model approach.