The site location of Nd3+ ions in congruent strontium barium niobate (Sr0.6 Ba0.4 Nb2 O6) has been systematically investigated by means of low-temperature optical and electron paramagnetic resonance spectroscopies. The experimental results obtained by these complementary techniques clearly indicate that Nd3+ ions are mainly located in only one of the four available cationic sites, the A2 sites, and preserving the Cs local symmetry of these host cation sites. The energy levels and g -factor value experimentally obtained by both techniques have been used to calculate the crystal field parameters for the Nd3+ ions in this A2 cationic site. © 2009 The American Physical Society.