The fading phenomenon of pendellosung fringes in diamond crystals has been studied by means of X-ray diffraction section topography. The fading periods of dynamical interference frihges have been observed in plate-like crystal and wedge-shaped crystal, as well as in crystal containing a stacking fault. They have been adequately interpreted in terms of dynamical diffraction theory. The quantitative comparison of experiment with theory has been made and the agreement is found to be quite good.