Archaeological leather objects are treated by lyophylization as well as chemicals to eliminate the harmful effects of drying. Preliminary treatment of the waterlogged leather objects is done by impregnation using polyethylene-glycol. Microscopy is used to study the process of solidification in the leather, as well as differential thermal analysis. The parameters of the lyophilization process are equally carefully determined. Certain circumstances, like the presence of metal associated with the leather or specially treated leather might require another procedure. -- AATA