Recently promising quaternary Cu2ZnSnS(Se)4 compounds for low cost absorber layers have attracted considerable interest. It is believed that these materials due to their low cost and abundance are alternative to the expensive absorber materials CuIn1 −xGaxSe2 (CIGS) of thin film solar cells, showing high conversion efficiency of 20% [1]. So far, the thin film solar cells over 9 % efficiency have been fabricated [2]. Cu2ZnSnS(Se)4 crystals were grown by the modified Bridgman method. The luminescence was excited by semiconductor laser with the wavelength 532 nm and the intensity 35 mW/cm2. The PMT-62 was used as a photodetector for sulfur-containing samples and InGaAs photodetector for selenium samples. For sulfur-containing samples a single peak, whose intensity quickly decreases with increasing temperature is observed (fig. 1a). For further analysis of the PL graphs the formula from [3] was used. The activation energy of the observed photoluminescence Ea ≈ 50 meV was determined by fitting the formula to the experimental data. The hot probe method shows that the samples have p-type conductivity. So it is assumed that the obtained activation energy corresponds to the acceptor level. Taking it into account the room temperature band gap value was found to be about 1.33 eV. Figure 1b shows the temperature dependence of photoluminescence spectra of the Cu2ZnSnSe4 sample. An analysis of obtained curves allowed us to assume that the high-energy peak is related to the recombination of electrons of the conduction band with holes from the acceptor level. Taking it into account the depth of the acceptor levels, the obtained band gap is found to be about 1.3 eV, which is close to the values given in [4]. The low-energy peak could be explained by the recombination of carriers from zone to deep impurity level. It is in contradiction with [5]. According to Babu et. al. [5] the band gap value is indicated to be 0.9 eV which corresponds to the low-energy peak. More detailed study should be done to clearly nature of PL of Cu2ZnSnSe4.figureFig. 1. Temperature dependence of photoluminescence of samples: a) Cu2ZnSnS4,; dotted lines show the shift of the peak intensity with temperature increasing; b) Cu2ZnSnSe4.