This study has been conducted to test if the yearling fleece characters may be predicted from the weanling fleece characters, by investigating the relationship between the weanling and the yearling fleece characters with special reference to the grease yield, clean yield, clean yield percentage, stretched length, density and the fineness of the Corriedale sheep wool. The animals used were 11 Corriedale ewes born in the spring, 1955 at the Chugoku Stock Breeding Farm of the Department of Agriculture and Forestry. The wool samples were taken from left and right side and thigh regions of each sheep at weanling and yearling ages and each fleece character at both ages was measured and its relationship was analyzed. The results obtained were as follows: (1) Considerably high and significant regressions and correlations were found between weanling and yearling characters, such as the grease wool yield, stretched wool length at side region and the wool fineness at thigh region. (2) While the clean wool yields, clean wool yields percentages, wool densities and the wool fineness at side regions between both ages had no significant regressions and correlations. (3) It seems from the results of the present study that of all fleece characters measured, grease wool yield, stretched wool length at side region and the wool fineness at thigh region have considerably high values for predicting the yearling fleece characters from the weanling characters of the Corriedale sheep.