During the past 10 years, about 30 large zinc sculptures have been restored in northeastern Germany, where an inventory set up by the Rathgen Research Laboratory lists about 200 individual objects. During the restoration of these sculptures, the extensive damage to this group of objects became obvious. Within a research project supported by the Deutsche Bundesstiftung Umwelt, the type of metal used for casting these sculptures, the original treatments of the surface, the corrosion phenomena, and the mechanism of decay have been studied. The results of these studies form a basis for efficient techniques for restoration and preservation. Also very important for future efforts for the conservation of cast zinc objects are the experiences from the treatment of about 30 sculptures since 1984. Alhough there are commonly accepted ideas on how to restore zinc sculptures, opinions differed on details. For instance the use of corrosion inhibitors or the way to join fragments, either by soldering or gluing, demand further laboratory research.