The Domestic Dog lives today in the industrial nations mainly as a companion animal of man and is not so much used or exploited anymore, as in earlier times or in other cultures. There exist the following forms of keeping ("keeping systems"): Keeping in apartments or houses, keeping in enclosures or pens, keeping the dog attached or chained, letting the dog roam freely and uncontrolled. The latter form will not be discussed. For the keeping of dogs in enclosures or chained, forms which are easier to detect, observe and control, there exist rather well-defined criteria for an evaluation of the keeping conditions, to a great extent based on the animal welfare legislation. Dogs in apartments or houses however are kept in the seclusion and privacy of human homes which makes an evaluation of the keeping conditions more difficult. Basically however, the same criteria are to be applied as to the other keeping forms. Keeping of dogs in apartments or houses is to be considered as appropriate for the animal, if certain requirements are met. Dog keeping includes being busy with the animal in different ways. Animal appropriate ways of treatment of and of occupation with the dog are therefore an integrative part of correct keeping conditions.