In this report models of granulation tissue formation during wound healing are reviewed. As suggested by Kovac and Rudas a distinction is made between inflammatory, foreign body and reparative granulation tissue formation. The advantages and disadvantages of the different models are discussed. While the older studies mainly compared qualitative evaluation of granulation tissue, in recent experiments models involving predominantly quantitative histological and biochemical methods are of increasing importance. One of these is a spongiosa implant model designed by our group which is briefly discussed.