This study was conducted to investigate the variations in clean wool yield percentage among body regions and the relative reliability of each clean yield of 8 regions for predicting the clean yield percentage of the entire fleece of the Japanese Corriedale sheep. The animals examined were 10 Corriedale yearling ewes born in the spring of 1954 in the chugoku Stock Breeding Farm of the Ministr of Agriculture and Forestry. The clean wool yield percentages of small wool samples taken prior to the shearing time at 13 to 14 months after birth, from each sheep in 8 body regions including withers, back, rump, shoulder, side, hip, belly and thigh, were compared with one another and with the clean yield percentage of the entire fleece.The results obtained are as follows.1. Higher clean yield percentages were obtained from the withers (55.42%), back (52.55%), rump (52.62%) and shoulder (52.44%) and lower percen tages from the side (50.94%), hip (51.60%), belly (51.05%) and thigh (49.58%).2. The mean clean yield percentage of the entire fleeces (47.33%) was lower than that of any one of the 8 body regions.3. The difference in the clean yield percentages among the individuals and among the regions was highly significant and the difference among the individuals was greater than that among the regions.4. Correlation coefficients between the clean yield percentages of small wool samples from the 8 regions and those of the entire fleeces showed different values among the body regions; higher coefficients were obtained from the rump, thigh, hip, belly and back and no significant coefficients from the withers, shoulder and side.5. From the results of the present study it seems that among clean wool yield percentages of the small wool samples from the back, rump, hip, belly and thigh, differences in accuracy for prediction of clean yield percentage of the entire fleece are so small and clean wool yield, percentage of each of these five regions would be adequate for use in predicting the clean yield percentage of the whole fleece.