Unlike articular erosions in the appendicular skeleton, the frequency, appearance, and clinical relevance of vertebral erosions in azotemic osteodystrophy are not known. Lateral vertebral radiographs of 118 patients on maintenance hemodialysis were reviewed to assess the frequency, distribution, and rate of progression of vertebral erosions. Thirty (25%) of 118 patients showed a superficial corner erosion resembling the so-called Romanus lesion of ankylosing spondylitis. Their presence, whether at a single level or at multiple levels, did not correlate with erosive changes in the phalanges or sacroiliac joints that are known to occur in renal osteodystrophy. Vertebral erosions may progress slowly with time, but seem to have limited bearing on clinical symptoms. In two patients, however, the radiographic changes progressed dramatically, simulating an infection. Biopsy and surgical intervention were considered but not carried out because one patient declined and in the other an infected graft was identified as the source of infection. Both patients had negative scintiscans, and their subsequent clinical courses excluded infectious spondylitis. Vertebral erosions in patients on maintenance hemodialysis are frequent, and there appears to be a spectrum of changes from superficial erosions to large resorptive defects. Further diagnostic evaluation of these erosive changes appears to be warranted only rarely.