Introduction: Fatigue and poor physical function are well-known symptoms in cancer patients. Allogeneic stem cell transplantation is an established treatment for certain cancer diagnoses, especially leukaemia. The aim of this study was to investigate physical function and fatigue in relation to allogeneic stem cell transplantation. Materials and methods: 21 patients awaiting allogeneic stem cell transplantation were included in a descriptive follow-up design. Fatigue and physical function was assessed by a standardized test programme consisting of a stair test, a test of maximum oxygen uptake and questionnaires on physical activity and fatigue prior to transplantation as well as 3 and 6 months after transplantation,. Results: 10 men and 11 women were included. The mean age was 39 years (19-60). Prior to transplantation patients had a low maximum oxygen uptake and reported more fatigue than the Danish general population. Physical fatigue rather than mental fatigue was pronounced both before and after transplantation. No significant changes in the parameters were found from before transplant to 6 months after transplant. Conclusion: The results indicate that prior to transplantation patients have poor physical function and increased physical fatigue. The symptoms seem to persist 6 months after transplantation. This could indicate a need for an extensive rehabilitation programme following transplantation.