Autofluorescence and transmission values of the lens for blue-green light were determined at two locations with the use of identical fiuorophotometers: in Coimbra, Portugal, in 44 healthy controls, 15 haemodialysis and 11 renal failure patients, and in Leiden, The Netherlands, in 57 healthy controls, 23 haemodialysis and 47 renal transplant patients. The increase in lens autofluorescence as a function of age was 42 % higher in the Portuguese controls than that in the Dutch controls (p < 0.001), but the lens transmission did not differ significantly (p = 0.21). Significant differences were found between the autofluorescence values of the Portuguese haemodialysis and renal failure patients and those of age-matched local controls (+18%, p = 0.009, and +26%, p = 0.03, respectively), as well as between the lens transmission values of the Portuguese renal failure patients and those of age-matched local controls (-2%, p = 0.03). In the renal transplant patients the average autofluorescence and lens transmission values were equal to those of the local controls (within 3 %) and independent of the number of anti-rejection treatments administered.