Two cases of Paneth's cell adenoma of the stomach are reported and their morphological, histochemical, immunohistochemical, ultrastructural and immunocytochemical features are described. Both surgical specimens showed varied dysplasia with severe atrophic gastritis and intestinal metaplasia. 60%-70% of the tumor cells contained coarse eosinophilic cytoplasmic granules that are PAS positive but unstained by alcian blue at pH 2.5, and exhibited positive antiserum immunoreaction for ly-sozyme. The Paneth's nature of these granules was confirmed by electron microscopy and immunoelec-tron microscopy. In addition, some endocrine cells were detected in the neoplastic glands. The characteristics of Paneth's cell adenoma of the stomach are discussed and a close relationship between the histogenesis and intestinal metaplasia is suggested.