ABSTRACT. With the aim of investigating bone mineral loss during maintenance hemodialysis (MHD), bone mineral content (BMC) was measured by means of two-dimensional scanning photon absorptiometry in 47 chronic renal failure patients on MHD 13 females (age range 22–50 years, mean dialysis duration 189 days) and 34 males (age range 23–69 years, mean dialysis duration 449 days). Measurements were carried out in most patients three times at an interval of 6 months. Initial mean BMC values were for both sexes significantly lower than normal, but did not correlate to duration of MHD. The longitudinal measurements demonstrated a highly significant decrease in BMC with time: the mean BMC values after 6 and 12 months, respectively, were for females 95.8 and 93.4% and for males 97.3 and 94.4% of the initial values with no significant differences between sexes. The fall in BMC did not correlate to duration of MHD, initial BMC value, or age. In some of the patients a substantial loss of BMC was observed, and it is suggested that these patients in particular may develop severe bone disease. A BMC method with high precision is mandatory for selection of such patients.