A 33-year-old woman developed acute bilateral pulmonary infiltrates after the intense use of rock cocaine (crack). She subsequently had progressive deterioration of pulmonary function to the point of being ventilator-dependent. Open lung biopsy showed a chronic interstitial pneumonia with extensive accumulation of free silica within histiocytes associated with mild pulmonary fibrosis. This pattern of interstitial pneumonia has not been previously reported in crack users.