The highly pathogenic filoviruses, Marburg and Ebola virus, are difficult to handle and knowledge of the interactions between filoviruses and their host cells remained enigmatic for many years. Two developments were crucial for the presented advances in our understanding of the cell biology of filoviruses, which is still fragmentary. On the one hand, the number of high containment laboratories increased where handling of the highly pathogenic filoviruses is possible. On the other hand, molecular biological tools have been developed that allow investigation of certain aspects of filoviral replication under normal laboratory conditions which considerably accelerated research on filoviruses. This review describes advances in understanding the interactions between host cells and filoviruses during viral attachment, entry, transcription, assembly and budding.