Although usually considered a feature in mushroom worker's lung disease, hilar adenopathy was not found and only 8 of the authors' 26 patients exhibited positive radiographic findings. The etiology of the disease is allergic with a radiographic appearance of alveolitis which may present with consolidation or a reticular pattern. None of the 26 patients exhibited enlargment of the hilar lymph nodes. The acute phase subsides in 10 days to 6 weeks after exposure has ceased.