Silicosis is one of the most prevalent occupational lung diseases and a public health problem throughout the world. Underground miners of copper and cobalt are exposed to the dust of these minerals and thus to the risk of developing silicosis. The objective of this report was to describe a series of silicosis cases in miners exposed to mineral dusts at a mining company operating since the colonial era in Lubumbashi, Katanga province, in the Democratic Republic of the Congo (DRC). This descriptive retrospective study reviewed records at the occupational safety and health department of the mining company mentioned above and included 2500 underground miners who worked there between 1970 and 1995; it collected and analyzed their medical records. Chest radiographs of silicosis patients were classified according to the ILO International Classification of Radiographs of Pneumoconiosis. All miners were males (mean age: 48.5 ±12.5), had low literacy levels, and used no protective device (i.e., mask) against dust. Their mean number of working years in the underground mines was 25.07±7.39 years. Of the 2500 miners, 1.08 % (27/2,500) had developed silicosis. The most common clinical manifestations were dyspnea and cough, and the most prevalent radiologic features large opacities (92.59 %), small opacities (96.27 %), and pleural thickening (25.92 %). The fatality rate was 100 %. This study revealed the absence of safety measures among Congolese underground miners from Lubumbashi, which might have contributed to the development of silicosis in some of them. It is thus necessary to implement occupational safety measures to reduce their risk of silicosis.