Under the auspices of the European Association of Hematopathologists and the Society for Hematopathology, 100 hematopathologists and clinicians have met together and in subcommittees over a 5-year period. The model used was that developed by the International Lymphoma Study Group, which used morphologic, immunologic, and genetic features. It resulted in the revised European-American Lymphoma classification. The newly proposed leukemia classification uses a similar format and eliminates purely morphologic subtypes that have no current clinical relevance. As with all consensus proposals, these classifications must withstand criticism and debate by potential users.