Histological sections of methacrylate-embedded bone marrow biopsies allow exact evaluation and classification of the cellular marrow components. We describe a simple method for preparation of sections of aspirated bone marrow particles following embedment in methacrylate. Comparison of histological sections from marrow particles and marrow biopsies demonstrated identical quality. Thus, preparation of methacrylate-embedded particle histologies will frequently abrogate the need for marrow biopsies performed in addition to a marrow aspiration. Routine preparation of both cytological and histological preparations from aspirated bone marrow allows more exact assessment of the bone marrow than cytological evaluation only.