The author intended in this study to evaluate radiographically sizes of the heart and left atrium and angiographic grades of regurgitation in relation to the duration of illness as well as pulmonary capillary wedge pressure (PCWP) in mitral insufficiency. Total twenty patients including eight males and twelve females who exhibited mitral regurgitation clinically were analyzed. The results obtained are as follows; 1. The duration of illness ranged from 6 months to 16 years. Mean duration according to grades of regurgitation was 7.3, 6.9 and 4.5 years in grades I-II, III and IV, respectively. It was revealed that the greater the extent of regurgitation shorter the duration of illness. 2. CT ratio was 63, 69 and 67 percents and diameter of left atrium was 5.3, 6.0 and 5.8cm in the grades I-II, III and IV, respectively. 3. No correlation between the extent of regurgitation and PCWP was demonstrable, the duration of illness was longer in the patients with low PCWP than in the patients wtih high PCWP. In contrast with the duration of illness. CT ratio and left atrial diameter were smaller in the patients wtih low PCWP than in the patients with high PCWP. 4. In the low PCWP group, CT ratio and left atrial diameter were greater in grades III-IV than grades I-II. On the other hand, no correlation between extent of regurgitation and CT ratio as well as left atrial diameter was evident in the high PCWP group.