Abstract This chapter describes the current models of patient-derived tumor xenografts (PDXs) established from hematologic disorders, stratified based on the 2008 World Health Organization Classification of Hematologic Tumors. A schematic introduction of human hematologic disorders is provided to the general readers as a tool for the description of the PDXs models. Available PDX of both myeloid and lymphoid origins are described in details, highlighting the utility of these models to define the therapeutic efficacy of current and novel drugs and/or therapeutic protocols.