Er-doped (100-x) SiO2-x SnO2 glass-ceramic monoliths were prepared using a sol-gel method. Raman spectroscopic measurements showed the structural evolution of the silica matrix caused by the formation and the growth of SnO2 nanocrystals. Analysis of the photoluminescence properties shows that the quantity of Er3+ ions embedded in the vicinity of SnO2 nanocrystals could be controlled by the SnO2 concentration. We give spectroscopic evidence of energy transfer to erbium ions provided by SnO2 nanocrystals in the silica matrix. The 4I13/2 level decay curves present a double-exponential profile with two lifetimes associated to rare-earth ions in two different environments.