OBJECTIVE: To inform clinical rheumatologists about the common and rarer hematological manifestations of rheumatoid arthritis with an emphasis on diagnosis and therapy and a particular reference to Felty's syndrome. METHODS: Literature review. RESULTS: The hematological manifestations can be conveniently categorized into the broad areas of; anemia, particularly NSAID induced iron deficiency anemia and the anemia of chronic disease, neutropenia, particularly Felty's syndrome and the large granular lymphocyte syndrome and drug induced neutropenia; thrombocytopenia, particularly autoimmune and drug induced thrombocytopenia; and hematological malignancy. Rarer conditions, their diagnosis and therapy are also described in this review. CONCLUSION: Hematological manifestations of rheumatoid arthritis are very common. A logical approach using easily available tests should allow straightforward decisions about diagnosis and therapy to be made, even in patients with some of the rarer manifestations.