DTA, XRD and sintering investigations of the system BaSnO 3 –BaGeO 3 , prepared by a mixed-oxide method, are described herein. The melting temperature of this system is about 1270±5°C. We find a partial solubility of BaGeO 3 into BaSnO 3 of the order of 6–7mol%. Up to 50mol% BaGeO 3 , the calcined powders (1150°C) as well as the once-sintered samples consist of BaSnO 3 and orthorhombic BaGeO 3 at room temperature. A gradual appearance of hexagonal BaGeO 3 can be observed in calcined powders and once-sintered ceramics with a BaGeO 3 content above 50mol%. After sintering at ≥1200°C for more than 1h all ceramic bodies consist of BaSnO 3 and orthorhombic BaGeO 3 . The addition of BaGeO 3 leads to a considerable reduction of the sintering temperature and to a strong densification. Sintering at 1180°C for 10h and an addition of only 1mol% BaGeO 3 leads to dense ceramic bodies with cubic-like grains.