Ferroelectric lithium-niobate (LiNbO 3 ) crystals obtained by glass crystallization were investigated. The glass samples of the composition within the system LiNbO 3 -SiO 2 -Al 2 O 3 were prepared by melting process and then subjected to crystallization by the heat-treatment method, at the appropriate temperatures, between 500 and 900°C and for the times 10-60 min. Transparent glass-ceramics could be obtained. It was shown that in the investigated system the Layton's criterion B/N > 1 has significant influence for the glass-ceramic's transparency. The Al 2 O 3 -content, according to Kokubo's suggestion, is not the primary factor for high nucleation rate in this system.IR absorption spectroscopy analysis of the prepared glass samples shows that in the obtained glass network, which consists of SiO 4 -tetrahedra and NbO 6 -octahedra, the lithium ions are situated in the holes of the network closer to NbO 6 -octahedra than SiO 4 -tetrahedra.XRD analysis of the crystallized glass samples shows that phase separation precedes the nucleation of LiNbO 3 in glass matrix. At 650°C, crystallization of LiNbO 3 is the most intensive.SEM analysis of the crystallized glass samples shows that the crystal size of LiNbO 3 increases with the increasing temperature and time of the heat-treatment. It could be seen that crystal growth is not classical, it takes place by nuclei coalescence within the clusters.The measured values of dielectric constant and refractive index, at a frequency of 1 kHz and at room temperature, are between those of the noncrystallized parent glass and the pure LiNbO 3 crystal.It could be concluded that the obtained transparent glass-ceramics based on LiNbO 3 crystals can be considered as a good ferroelectric material.