A 39-yr-old black female, with a history of partial gastrectomy, presented with worsening low back and left hip pain. Initial evaluation revealed an elevated sedimentation rate, the presence of antinuclear antibodies, and the absence of rheumatoid factor. Prednisone therapy, for early seronegative rheumatoid arthritis, was of minimal benefit. A bone scan showed radionuclide uptake in the left sacrum. Subsequent biopsy revealed a healing fracture. The pain later involved both hips, knees, feet, hands, spine, shoulders, and ribs. Laboratory evaluation revealed hypocalcemia, hypophosphatemia, a 25-hydroxyvitamin D level of 12 ng/mL (normal, 9-52 ng/mL), and an intact parathyroid hormone level of 304 pg/mL (normal, 10-65 pg/mL). The initial bone density by dual energy X-ray absorptiometry of the lumbar spine was 0.871 g/cm(2) (T-score -1.81) and of the femoral neck, 0.553 g/cm(2) (T score -3.84). Vitamin D and calcium therapy corrected the vitamin D deficiency and secondary hyperparathyroidism, with resolution of pain over the ensuing 4 mo. A repeat bone density 2 yr later revealed a 23.7% increase in the lumbar spine and a 36.2% increase in the femoral neck. Clinical osteomalacia results from long-standing vitamin D deficiency. Treatment can result in resolution of bone pain, while producing marked increases in bone density.