The system poly(ether ether ketone) (PEEK)/PET-PHB 60 has been studied by differential scanning calorimetry and scanning electron microscopy (SEM). The thermal analysis data, especially the glass transition temperatures, indicate that the blends are compatible. The SEM analysis seems to confirm this, showing a mostly homogeneous structure. When the two phases are still evident, a good adhesion is shown; this is of interest in terms of the mechanical properties, results for which are not yet available.