Virus isolation is an important and critical method used for the diagnosis of emerging and re-emerging viral pathogens. The process involves the use of in vitro cell culture (most common) or suckling mice and relies on proper handling and storage of the samples prior to testing. Here we describe the procedures for in vitro virus isolation of the tick-borne bunyavirus Dabie bandavirus, also called severe fever with thrombocytopenia syndrome virus (SFTSV), which causes a hemorrhagic febrile illness with mortality rates as high as 50%. This chapter also describes the methods for proper quantification of Dabie bandavirus for follow-up virological investigations.