Allogeneic bone marrow transplantation is limited by the availability of suitable HLA-matched donors and the risk of graft versus host disease (GvHD). In an attempt to overcome these limitations umbilical cord blood (UCB), has become a further alternative. UCB transplantations in Austria were started in 1991. As of September 31, 1998, six patients have been transplanted. Diagnoses were severe aplastic anaemia (SAA) (n = 2), acute lymphoblastic leukaemia (ALL) (n = 1), familial hemophagocytic syndrome (FHL) (n = 2) and chronic myelomonocytic leukaemia (CMML) (n = 1). Three patients received UCB grafts from HLA-identical siblings and three patients from unrelated donors, of whom two were disparate at two HLA loci (A/B) and one mismatched at one locus (C). Five patients were engrafted with complete donor hematopoiesis, with a median time of 26.5 days (range 14 to 39 days) to an ANC count of > or = 0.5 x 10(9)/L and a median time of 42.5 days (range 24 to 67 days) to a platelet count of > or = 20 x 10(9)/L. One patient with FHL had partial engraftment and died due to reactivation of cytomegalovirus (CMV) infection and CMV pneumonia on day +25. Of the five patients surviving the post-transplant period, one with CMML had a relapse on day +128 and died after a HLA-matched bone marrow transplantation from the same sibling donor in the second relapse. Another patient with ALL relapsed on day +200 but is still alive under palliative treatment; one patient with SAA showed graft rejection and autologous hematopoietic reconstitution and later had a successful CD34(+)-selected allogeneic peripheral stem cell transplant from a C-locus mismatched unrelated donor. Two patients (one with SAA and one with FHL) are alive with complete remission of the underlying disease. This report reflects the experience and results of UCB transplantation in Austria and discusses the position of UCB transplantation in the context of the other stem cell alternatives available today.