BACKGROUND It is still not known whether hematopoiesis reconstituted by autografting with the peripheral blood hematopoietic progenitors (CPCs) after myeloablative high dose radiotherapy and/or chemotherapy is durable and capable of coping with the increased demand imposed by boost radiotherapy, surgery, or infection. METHODS The durability of hematopoiesis was evaluated in 34 consecutive cancer patients treated with myeloablative total body irradiation (n = 17, median follow-up 3 years, range 3-49 months) and/or alkylating-agent chemotherapy (n = 17, median follow-up 8 months, range 6-41 months) and autografted with CPCs because bone marrow autografting was contraindicated. CPCs (> or = 8 x 10(6) CD34 + cells/kg) had been collected during mobilization into the circulation in response to previous anticancer therapy and hematopoietic growth factor(s). RESULTS Following brief temporary pancytopenia, all patients achieved normal and durable hematopoiesis. The newly reconstituted hematopoietic system was capable of reacting favorably to stressful and debilitating events such as surgery, radiotherapy, or varicella-zoster infection. No secondary irreversible failure of blood cell production occurred. CONCLUSIONS The documentation of the durability of normal hematopoiesis following myeloablative cancer therapy and autografting with mobilized CPCs implies that the latter procedure, rather than being solely an alternative to bone marrow autografting, represents an advantageous tool of choice permitting substantial amelioration of the therapeutic index of high-dose cancer therapy.