This study aimed to determine the occupational and clinical characteristics of patients with progressive massive fibrosis (PMF) and factors related to the development and severity of PMF. Personal, occupational, radiological, and functional findings of 129 patients diagnosed with PMF were evaluated. Sandblasting workers were found to be diagnosed with pneumoconiosis at an earlier age than those in other professions. The dust exposure durations of sandblasting and ceramic workers were significantly less than those of workers in other occupations. Statistically, a significant negative correlation was found between lung functions and small opacity size, small opacity profusion score, and large opacity size. No relationship was found between large opacity size and smoking status, concomitant tuberculosis, and duration of dust exposure. An effective surveillance system that considers factors that accelerate pneumoconiosis progression should be established.