The quantitation of B lymphocytes in paraffin-decalcified bone marrow sections is often used as supportive evidence of primary or residual B-cell lymphoproliferative disorders; however, well-defined normal ranges for B lymphocytes are not available. Thirty-four B5-fixed decalcified bone marrow sections were analyzed from a group of patients having an essentially normal bone marrow morphologic examination and lacking any evidence immunologic or hematopoietic disease. All samples were stained with CD20, CD45RA (4KB5), and DBA.44 for B cells, and CD45RO (UCHL-1) for T cells. Image analysis was performed on all cases. CD20-positive cells ranged from 0% to 5.97%. CD45RA positivity ranged from 0% to 5.48%. DBA.44 was positive in 0% to 2.07% of the cells. CD45RO positivity varied from 0% to 6.7%. These results provide useful immunohistochemical B-lymphocyte reference ranges in B5-fixed paraffin bone marrow sections.