Introduction: There are few data concerning variation over time of mineral and bone metabolism disorder (MBD) in prevalent chronic dialysis patients (CD) in Argentina. Methods: 3-years-period time 2011-2013 data from Argentine Registry of Chronic Dialysis was used. Demography, Chronic Renal failure etiology (CRF) and MBD biochemical variables in CD prevalent patients, were analyzed. Results: Prevalent population grew from 26572 to 27966 patients between 2011 and 2013, basically as a consequence of incidents growth. Age increased from 57.2 (± 17.0) to 57.5 (±16.9). In both sexs =65 years old rate increased, more in men. Diabetic Nephropathy is the first etiology (27.2%). Between 2011 and 2013 there is a significant decrease of PTHi (p=0.001) average values. In 2013, 25.5% showed between 150 to 300 pg/ml values, 22.9% < 150, el 27,8 % between 300 and 600, and 23.8% showed >600 pg/ml values. The lowest PTHi values can be observed in elderly, males, diabetic pattiens and in the first years under CD treatment. Conclusions: Average PTHi, as well as patients with over 600 pg/ml percentage decreased, but the adequate range patients percentage (150-300) remained unchanged. Average PTHi decrease is due to the progressive increase of sub-populations less likely to develop hyperparathyroidism: elderlypeople, males, diabetics and new patients.