We describe a patient with a 23-year history of progressive calcinosis and features of the CREST syndrome (calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, telangiectasias) who was treated with diltiazem, 240 mg/day, for 5 years. No clinical exacerbation of calcinosis occurred during treatment. Radiographs showed no new lesions, and there was reduction in the size of the existing lesions. Bone scans revealed a progressive decrease in the uptake of the radionuclide by soft tissue foci. We propose that diltiazem may stop the progression of calcinosis by reducing the cellular calcium influx in affected tissues.