Between 1992 and 2005, 72 cases of occupational hypersensitive pneumonitis were reported to the Czech National Registry of Occupational Diseases. This represented 0.24% of all occupational diseases reported in the Czech Republic during that period. The greatest number of cases occurred in 1997 (10 cases), of which men constituted 58.3% (42 cases) and women 41.7% (30 cases). The most prevalent cases were farmer's lung (50 cases), malt worker's lung (7 cases) and chemical worker's lung (6 cases). Agriculture was the most common economic activity (total 48 cases), with cattleman and dairyman (total 26 cases) the most frequent occupations; less common were tractor driver (8 cases) and maltster (7 cases). Typical case reports after different exposures are presented. A peak in frequency was observed in the age groups of 45-49 and 50-54 yr (20.8% and 19.4% of cases, respectively) and within the first four years of employment (22.2% of cases). Median age was 48 yr and median exposure 12.5 yr. Incidence was in the range of 0.00-0.20 per 100,000 workers, which appears rather low. Due to the difficult diagnostics of hypersensitive pneumonitis, the actual number of cases is undoubtedly higher, and this disease is probably under-reported.