We examined, in one family, 5 cases of hypertrophic cardiomyopathy (HCM) with a similar pattern of left ventricular inflow (LVIF) and distribution of hypertrophy. Its clinical background and significance were discussed. Because a variety of morphologic expressions of HCM may be observed in the same family, distribution of left ventricular hypertrophy (LVH) varies in even first-degree relatives of the family. In all five cases in this study, however, LVH was localized between the anterior wall and the interventricular septum. On the other hand, typical pattern of LVIF in HCM is "decreased peak velocity and prolonged deceleration time of the early diastolic wave (E), and compensatory augmentation of the atrial contraction wave (A)". All of the five cases in this study had a pattern of three characteristic peaks of LVIF, which showed the mid-diastolic wave between the E and A waves. The above findings suggested that the myocardial characteristics of the five cases in this family were very similar, and could be important clues clarifying the mode of inheritance of HCM.