The synthesis of BaSnO
3
powders has been investigated at lyothermal conditions (temperature of 250 °C; t = 6 h), starting from SnO
2
·
x
H
2
O and Ba(OH)
2
and methanol, ethanol, isopropanol and acetone as solvents. Among them isopropanol was found to be the most suitable medium for preparing BaSnO
3
. By addition of the modifier Genapol X-080 during the processing, the BET specific surface area of the end-powder was increased by a factor of 10. The as-prepared powder consisted of BaSn(OH)
6
. The thermal behavior, the crystallization behavior and the structure evolution of the powder during heating treatment have been studied with the TG-DTA-MS, XRD and FTIR. The weight loss of the as-prepared powder of about 12 wt% heated up to 1200 °C is mainly attributed to the dehydration around 260 °C which leads to the structure rearrangement and the building of the [SnO
6
] octahedra. At this temperature BaSn(OH)
6
converts to an amorphous phase, from which BaSnO
3
nucleates and grows with increasing temperature. The obtained BaSnO
3
powders had a BET specific surface area of 16.56 m
2
/g and a primary crystallite size of 49 nm.