Flow cytometry laboratory plays an integral part in the evaluation of a BMT patient. Its role starts at the time of clinical presentation to assure most accurate and reproducible disease diagnosis and subclassification. This can only be achieved if the flow cytometrist is fully qualified in the diagnosis of hematolymphoid neoplasia and is able to correlate each and every case with morphologic data. Flow cytometric report, therefore, includes a standing diagnosis and goes beyond the sole description of an abnormal/atypical population. Following initial diagnosis, generated data are carefully stored and are retrieved for review whenever needed particularly during the evaluation of the remission status, response to chemotherapy, relapse, staging and detection of residual disease in marrow and apheresis product. Our laboratory performs leukemia/lymphoma assessment of approximately 150-200 samples a month in addition to 3-8 weekly apheresis procedures, 25-30 post-BMT immune monitoring samples and other isoteric assessments including CD4 counts for HIV population, HLA B27 evaluation, platelet/leukocyte antibodies, reticulated platelets, immunodeficiency disorders etc. This multidisciplinary center allowed us to develop a substantial expertise in the field, which hopefully benefits our patient, clinicians and fellow cytometrists. We are please to share our expertise at this distinguished forum.