Since 1939, it has been known that, silicosis and extrinsic allergic alveolitis can be seen among dental technicians. The interstitial disease caused by the exposure to complex substances used by dental technicians is classified as a special group called dental technician's pneumoconiosis. A 36-year-old man, who has no smoking history, presented with severe dyspnea. He had worked in different dental laboratories for 22 years, but he did not have respiratory symptoms until five years ago. After that date, he had hospitalized and had been examined for respiratory pathologies for many times. He had came to our clinic, because of the progression of his dyspnea. Diffuse pulmonary parenchymal infiltrates which can be related with pneumoconiosis and chronic type 1 respiratory deficiency had been diagnosed as the result of the examinations. While he has no history of smoking or any other risk factors or diseases in his medical history, the case was accepted as dental technician's pneumoconiosis. The factors related with the pathogenesis of dental technician's pneumoconiosis are; the complex compound of the substances (metal dusts, silica, plaster, wax and resins, chemical liquids, methyl methacrylate) used in this sector and their effects on the lung parenchyma. Extrinsic allergic alveolitis related with methyl methacrylate has been reported. The most important factor to acquire an occupational lung disease is a complex occupational exposure. The insufficient workplace airing and the lack of preventive measures added on this exposure, the risks become much more greater.