Typical defects of the cast engine blades from Ni base superalloys in the as-cast state and after long operation were investigated: the cast porosity, internal and external microcracs. The initial cast porosity and voids, which have appeared during long operation, reduce the fatigue and other service characteristics of the blades from Ni base superalloys. Hot isostatic pressing (HIP) reduces the size and number of micropores in the cast blades from Ni base superalloys with a polycrystalline (alloy GS6U) and single crystal (alloy GS32) structures. As a result, HIP improves the mechanical properties of the blades. Application of the HIP, together with the standard heat treatment in the renovation of the blades after long operation can provide a virtually complete restoration of their structure and efficiency.