Muscle function declines with age and progressive uraemia. We examined whether elderly predialysis patients could improve thigh muscle function, walking capacity, and functional mobility to the same extent as elderly healthy subjects when participating in 12 weeks of individual muscle endurance exercises for the thigh as well as in a low-intensive group programme. The uraemic exercise and comparison groups comprised 16 patients (age 76 +/- 7 years, glomerular filtration rate 18 +/- 5 ml/min) and 9 patients (age 72 +/- 6 years, glomerular filtration rate 16 +/- 5 ml/min), respectively. The healthy exercise and comparison groups comprised 18 subjects (age 75 +/- 7 years) and 5 subjects (age 79 +/- 4 years), respectively. Muscular strength, dynamic endurance, walking capacity, and functional mobility increased significantly in both the uraemic and the healthy exercise groups after 12 weeks of regular muscle endurance exercise training, whereas there was no significant change in static muscle endurance and quality of life in either group. None of the values changed for the uraemic comparison group nor the healthy comparison group during the observation period. Elderly predialysis patients had lower muscle function and mobility as compared with elderly healthy subjects, but were able to improve both after 12 weeks of exercise training to the same extent as elderly healthy subjects.