Information on 17,206 haemopoietic precursor cell transplants performed in 12 European countries between 1991 and 1993 was used to assess the number of transplants per million inhabitants per year by principal indication and donor source. 16.6 transplants were performed per million inhabitants per year with a range of 9.4-27.7. Differences between countries may be due to the availability of beds and resources or to divergent opinions about treatments. We used the coefficient of variation (CV) to assess the degree of agreement between clinicians with regard to different procedures and indications, with a cut-off of < or = 45% to indicate consensus. The rate of allogeneic transplantation between the 12 countries was more 'homogenous' than that of autologous transplantation (mean 6.8 per million inhabitants, range 5.2-9.5, CV 20% versus mean 9.8 per million inhabitants, range 3.6-18.4, CV 40%). Consensus was found for allografting in chronic myeloid leukaemia (CML) in first chronic phase (CV 19%), CML in later phases (CV 31%), acute myeloid leukaemia (AML) in first complete remission (CV 41%), AML beyond first complete remission (CV 34%), acute lymphoblastic leukaemia beyond first complete remission (23%), and severe aplastic anaemia (29%). Consensus for autografting was observed for Hodgkin's disease (CV 44%), non-Hodgkin's lymphoma (CV 44%), and AML beyond first remission (CV 41%). With this method an assessment of medical opinion can be made in spite of the different availabilities of resources. These data reflect the state of the art in haemopoietic precursor cell usage in Europe; they provide a basis for patient counselling and health-care planning.