This experiment was conducted to study the effects of dietary polyunsaturated fatty acid (PUFA) ratios on leukocyte subset composition in peripheral blood of growing Yangzhou geese. A total of 160 21-day-old healthy Yangzhou geese were randomly divided into 4 groups with 4 replicates per group and 10 birds per replicate (5 male and 5 female). The geese in the 4 groups were fed experimental diets with different ω-6/ω-3 PUFA ratios, including 12︰1, 9︰1, 6︰1 and 3︰1, respectively. The blood sample was obtained to make blood smear slide, and differential leukocyte counts were carried out at the age of 42, 56, and 70 days, respectively. The results showed as follows: compared with the 12︰1 and 9︰1 groups, lymphocyte percentage in 6︰1 and 3︰1 groups was significantly increased (P<0.01), whereas heterophil percentage and heterophil/lymphocyte ratio were significantly decreased at all detected ages (P<0.05 or P<0.01). Monocyte percentage in 3︰1 group was significantly higher than that in 12︰1 group at the age of 42 and 70 days (P<0.05). Additionally, compared with 12︰1 and 9︰1 groups, eosinophil percentage at the age of 56 and 70 days and basophilic granulocyte percentage at all detected ages in 6︰1 and 3︰1 groups were significantly decreased (P<0.05 or P<0.01). In conclusion, dietary ω-6/ω-3 PUFA ratios can affect the leukocyte subset composition in the peripheral blood of growing Yangzhou geese, and diet with low ω-6/ω-3 PUFA ratios (6︰1 or 3︰1) can decrease the percentage of eosinophil and basophilic granulocyte and heterophil/lymphocyte ratio, while increase the monocyte percentage. ［Chinese Journal of Animal Nutrition，2011，23（3）：492-498］