Delimed pelt trimmings are trimmings that are obtained from limed pelt trimmings by removingrnlime. Limed pelt trimmings are one of the solid wastes that are generated in leather processingrnwhich is common in Ethiopia unlike other countries. These wastes are important resources forrnproducing collagen hydrolysate which can be applied in leather processing operations. The aimrnof this study is to prepare collagen hydrolysate from delimed pelt trimmings and to apply it inrnwet blue goat skin in post tanning operation to determine the optimum hydrolysis conditions andrnmolecular weight of the collagen hydrolysate. And also to determine its stabilizing effect onrncollagen fibers by treating rat tail tendon with the collagen hydrolysates by carrying outrnenzymatic and thermal stability experiments. The optimum conditions of hydrolysis for postrntanning operation was determined by preparing six different types of collagen hydrolysates andrnapply it post tanning operation as a retanning agent. Based on the absorption of chemicals andrnorganoleptic properties, the best collagen hydrolysate is selected and characterized further usingrnFPLC and MALDI. The results showed that collagen hydrolysates play a role in stabilizingrncollagen fibers. And also the best collagen hydrolysate for post tanning is obtained when thernproportion of high molecular weight to low molecular weight proportion of the fractions is 80%rnto 20%. And the range of the molecular weight should be in between 2000 to 6000 daltons. Thisrncan be achieved when the hydrolysis condition is carried out by using 0.8% trypsin for durationrnof 3 hours. It is concluded that by preparing collagen hydrolysates syntans from delimed peltrntrimmings satisfactory results can be achieved by applying it in post tanning operation duringrnleather processing and also they can be used for stabilization of collagen fibers.