The authors review in this paper the most recent knowledge on possible toxic effects of manganese on the organism in the conditions of environmental exposure. A problem of cardiovascular manifestation is discussed in particular although it is not characteristic of chronic manganese intoxication. The results of animal studies s show that manganese ions may affect the heart. The effects of chronic exposure to manganese should incline us to reduce environmental exposure to this metal, and the existing controversies encourage to conduct further investigations in this area.