34 patients with chronic renal failure, 20 on periodic hemodialysis and 14 without dialysis, were evaluated for defects in iron stores, folic acid deficiency and renal osteodystrophy. A high incidence of abnormalities in iron stores was observed on bone marrow biopsy. The estimation of iron stores by means of serum iron and percent saturation measurements were unreliable. Significant folic acid depletion was an infrequent finding. The biochemical measurement of serum calcium or inorganic phosphorus had little predictive value in terms of renal osteodystrophy as demonstrated on bone marrow biopsy while serum alkaline phosphatase changes were of limited usefulness. Dialyzed patients generally had lesser abnormalities in iron studies as well as in bone assessments. The study suggests that bone marrow biopsy is a more reliable method of evaluating patients with chronic renal failure for iron abnormalities as well as for osteodystrophy as compared to the usually employed laboratory tests.