Bone marrow aspirates were obtained by sternal puncture prior to sternotomy in 54 volunteers (40 males and 14 females) aged 60 years or more. All underwent surgery for cardiological diseases and had normal blood counts, without any haematological abnormalities. Quantitative examination of these bone marrow aspirates yielded reference ranges for each cell type similar to those obtained in younger adults. However, qualitative analysis revealed certain discrepancies: dysplastic changes were observed frequently, mainly in megakaryocytes and erythroblasts, with a normal growth pattern of haematopoietic progenitor cells. A low proportion of macrophages and mast cells were noted in 30% of the bone marrow aspirates. Lymphoid aggregates, seen in 13% of these samples, were generally of moderate size, contained few mast cells and were non-clonal on immunophenotypic analysis.