Nanosized Li(y)MnSiO(x) and LiMnPO(4) have been synthesized by a hydrothermal route. Simply by changing parameters such as metal precursors and/or template, high surface area Li(y)MnSiO(x) with different morphology and sizes were prepared, in particular hollow spheres and plate-like nanoparticles, however with poorly developed crystallinity. In the case of LiMnPO(4), highly crystalline nanocrystals were prepared.