From a patient with chronic kidney failure. A bone marrow biopsy was done for the differential diagnosis of anemia. Suboptimal decalcification helped delineate the mineralized (bluish) and unmineralized bone (osteoid) nicely. Towrds upper left an area of active resorption is seen while lower left part shows osteoblasts busy lying down osteoid. However, wide osteoid seams remain unmineralized. These findings and a slight degree of peritrabecular fibrosis are characteristic of renal osteodistrophy.