RESUMO
OBJECTIVE: to analyze the frequency and importance of pneumoconiosis in affiliated workers to Instituto Mexicano del Seguro Social. MATERIAL AND METHODS: it was carried out a transverse, observational and comparative study; the behavior of the qualified pneumoconiosis was revised 1994-2004. The analyzed variables were sex, age, occupation, permanent disability and economic activity. It was carried out the analysis of absolute frequencies and rates. RESULTS: it was registered 14,827 cases; the rate for 10,000 workers oscillated from 0.48 to 2.39. The 99 % were presented in males, with 14,262 cases with permanent disability (rate: 96.89 per 100 cases of pneumoconiosis); employments with more frequency were miners, quarry workers and bricklayers. The average of permanent disability for pneumoconiosis in the period was of 11.09 to 15 %. States with a higher number of cases were Coahuila, Zacatecas and Hidalgo. Economic activities with a greater incidence were the extraction and benefit of mineral coal, graphite and metallic and non-metallic minerals. CONCLUSION: cases of pneumoconiosis have been decreasing, but even the determination of diagnosis is delayed, and due to this most workers have irreversible sequelae.