Silicosis and coal workers’ pneumoconiosis (CWP) a.k.a. black lung disease are two forms of occupational dust disease that give similar imaging appearances, but are caused by different pathologic changes within the lungs. Silicosis is the more fibrotic of the two entities and can be an isolated disease process or overlap with, and be part of CWP. Imaging changes in silicosis begin with the simple type of disease process, in which the interstitial changes appear as small rounded opacities (micronodules) called silicotic nodules, occur in the upper and the middle lung zones. With increasing amounts of free crystalline silica exposure, the complicated type occurs when progressive massive fibrosis (PMF) a.k.a. “large opacities” develop. Although coal workers’ pneumoconiosis looks like silicosis, the silicotic nodules are more likely to be larger and more sharply defined, with the greater likelihood to develop into progressive massive fibrosis (PMF).