The purpose of this study was to find the cause of starvation of paulownia tree affected by witches'-broom, and compared the rate of translocation of carbohydrates from the leaves of healthy tree with that from the leaves of the witches'-broom infected tree. Upper 5 leaves of each of healthy and diseased trees collected at the time just before sunset (A) and at the time before sunrise (B) of the successive days, were dried and prepared for the analysis. Samples were collected at three successive months from July to September. Total carbohydrates (starch and sugars), water soluble-, proteinic-, and total nitrogen were measured. The results were as follows. 1, The amount of the total carbohydrates of the diseased leaves was 50 per cent greater than that of the healthy. 2. The diseased leaves had about 70 per cent total nitrogen, about 80 per cent soluble nitrogen, and about 70 per cent proteinic nitrogen against each 100 per cent of the healthy. 3. C/N ratio of the diseased leaves was twice as much as the healthy. 4. The loss of total carbohydrates from the diseased leaves during night was 6.6 per cent and that of the healthy was 5.3 per cent. 5. The increase of total nitrogen during night was 0.04 per cent in the healthy and 0.28 per cent in the diseased leaves, and that of proteinic nitrogen was O.05 percent in the healthy and 0.3 per cent in the diseased leaves, while the change of soluble nitrogen contens during night was negligible in both of the healthy and the diseased leaves. Witches'-broom disease of paulownia which belonged to the viruses of the yellow group, contained much higher contents of carbohydrates and showed higher C/N ratio in the leaves of the diseased trees, although accompanied by their declined photosynthetic power. Net translocated carbohydrate quantities (apparent loss of carbohydrate contents-loss of the same during protein synthesis) from diseased leaves during night was much lower than that of the healthy and "the translocation ratio" ― loss of cabohydrate contents from leaves/whole carbohyqrates contained in the leaves at the beginning ― was also much lower than that of the healthy. It was concluded that the declined translocation power of the diseased leaves was the cause of excess carbohydrate contents in them and in turn accelerated the starvation of the diseased shoots or whole plant.