Sixty-three periapical granulomas were histologically examined. They were divided into four types: exudative, granulomatous, granulofibrous and fibrous types. The most frequent forms were the granulomatous types. The granulomatous type consisted of four zones: necrotic, exudative, granulomatous and fibrous. In the granulomatous zone lymphocytes, plasma cells, macrophages, Russel bodies, foam cells, neutrophil leukocytes were found. Mast cells were found in the fibrous zone among the collagen fibres.