Abstract:Hypercalcaemia occurring after ten weeks of immobilisation was observed in four adult patients all of whom had had prior renal failure sufficient to require renal dialysis. In all patients parathyroid hormone levels were normal or low and in three plasma 1,25(OH)2D3levels were low. These findings are consistent with immobilisation induced increases in bone calcium resorption. Renal excretion of calcium may have been impaired by renal dysfunction resulting in hypercalcaemia and suppression of plasma PTH and 1,25(OH)2D3levels. Resolution of the hypercalcaemia was associated with remobilisation. Parathyroidectomy is inappropriate treatment.