Aplastic anaemia (AA) is characterized by pancytopenia and bone marrow (BM) hypocellularity. In some patients AA may be mediated by T cells. To localize inflammatory cell infiltrates, we carried out a quantitative immunohistochemical analysis of BM biopsies of AA patients. In five out of eight biopsies, significantly higher numbers T cells were found in the areas with residual haemopoiesis (RH). The significantly increased numbers of CD3+ T cells in areas with RH supports the hypothesis of a site‐directed infiltration and/or a local proliferation of T cells in the BM of patients with AA.