In recent years,"the fluorescent imaging techniques"has made rapid advances, it has become possible to observe the dynamics of living cells in individuals or tissues. It has been considered that it is extremely difficult to observe the living bone marrow directly because bone marrow is surrounded by a hard calcareous. But now, we established a method for observing the cells constituting the bone marrow of living mice in real time by the use of the intravital two-photon imaging system. In this article, we show the latest data and the reports about the hematopoietic stem cells and the leukemia cells by using the intravital imaging techniques, and also discuss its further application.