It is the purpose of this communication to review briefly the factors which may be important in the prevention and management of renal osteodystrophy in patients undergoing long-term hemodialysis. It will be readily recognized that some of the recommendations will be supported by much experimental and clinical data whereas others will be much more speculative. Our justification is based not only on some theoretical reasoning but also on the fact that symptomatic bone disease has been absent in our own patients for a 5½-year period. Two very important general points should be emphasized before dealing with individual pathologic conditions. These are that adequate diet and dialysis are essential if progressive bone disease is to be avoided. We cannot solve the semantic difficulty associated with the word "adequate" and the problem is compounded by the multitude of different systems, dialyzers, and diets currently in use. Evidence is available that a proteinand