OBJECTIVE Autologous bone marrow transplantation (ABMT) is frequently used in the treatment of neoplastic diseases. It involves several manipulations of bone marrow cells in vitro that can damage the stem cells responsible for grafting. Long-term marrow cultures (LTBMC) support hematopoiesis in vitro for several weeks. We analyzed the effect of bone marrow cryopreservation on haematopoiesis when using this technique. METHODS 9 bone marrow from healthy donors (Group A) and 15 from patients who were about to undergo ABMT (Group B) were assayed in LTBMC. In all cases, cultures were initiated after cell concentration and also after cryopreservation in group B patients. Adherent cell layer formation, supernatant nucleated cell counts and CFU-GM growth from the non-adherent fraction were assessed. Statistical analysis were evaluated using Wilcoxon test for paired results and Mann-Whitney test for unpaired results. RESULTS No significant statistical differences were observed when the LTBMC from group A controls were compared to those from group B patients prior to cell cryopreservation. There was a significant statistical difference between cumulative cell recoveries among the cultures developed prior to and after cryopreservation of BM cells from group B patients. CONCLUSIONS The results supports the use of LTBMC to obtain information on the extent of the injury of BM cells during manipulations.