Given the shortage of donor kidneys for transplantation, we have focused on the use of non heart-beating (NHB) donor kidneys since 1982. The major drawback for the use of NHB donor kidneys is the inherent possibility of severe ischaemic damage leading to primary non function. Thus viability assessment of ischaemically damaged kidneys is crucial, and, therefore, a machine perfusion programme was reinstituted in 1993. Machine perfusion (MP) enables viability assessment through analysis of perfusion characteristics and measurement of enzyme release into the perfusate. Of the last 100 consecutive MP NHB donor kidneys, 71 kidneys were transplanted and 29 kidneys were discarded. Nine kidneys started functioning immediately, 51 kidneys showed delayed function and 11 kidneys never functioned. When analysing in retrospect different parameters for viability assessment, only α-GST, an enzyme specific for damage of proximal tubular cells within the kidney, could discriminate between functioning and non-functioning kidneys. With this promising viability assessment, the large NHB donor potential and the good transplant results, we recommend the use of these donors.