Mitochondrial morphogenesis in 31 strains of 9 species of Agaricus--A. arvensis Schaeff., A. bisporus (Lange) Imbach, A. bitorquis (Quel.) Sacc., A. campestris L., A. excellens (F. H. Moller) F. H. Moller, A. macrocarpus (F. H. Möller) F. H. Möller, A. silvaticus Schaeff., A. silvicola (Vittad.) Peck, A. xanthodermus Genev--and 2 strains of Pleurotus--P. ostreatus (Jacg.) P. Kumm., P. pulmonarius (Fr.) Quel.--has many common features in mitochondria distribution under favorable growth conditions (type 1) and in reconstruction of chondriom (fission or fragmentation) under unfavorable growth conditions and aging (type 2). The first type of mitochondria distribution was observed in heterokaryotic mycelium of some Agaricus strains and Pleurotus grown in agar medium during 7-14 days, and also in submerged mycelium of some Agaricus strains and Pleurotus. The second type of mitochondria distribution was observed in homokaryotic Agaricus strains under condition of starvation, in aging mycelium (28 days of growth), and in submerged mycelium of most of Agaricus strains. The first type of chondriom consists of small granular mitochondria in the apical cells and long snake-like network in subapical cells, and restores almost completely the mitochondrial network in the aging mycelium cells. The second type of chondriom consists of small granular mitochondria in all cells of mycelium. The surface of chondriom type 2 mitochondrial membrane was usually closely associated with ribosomes and changed crists. Such mycelium cells in A. bisporus strain Bs94 were TUNEL positive. So, the types of mitochondria morphogenesis in the Agaricus and Pleurotus mycelium cells are similar at different time and growth conditions and depend on complex of physiological and biochemical process in the mycelium cells.