The NMDA receptors are ionotropic glutamate receptors that are involved with a great number of different functions in the nervous system and in the retina in particular. They are composed of NR1 and NR2 subunits. The NR1 subunit derives from a single gene and has eight splice variants. The NR2 subunits, NR2A-D, arise from four different genes. The NMDA receptors are well studied in mammalian retina. However, scanty information exists about these receptors in the lower vertebrate retinas. That's why the aim of the present study was to investigate the distribution of NR1, NR2A and NR2B subunits of the NMDA receptors in frog retina. The indirect immunocytochemical method was applied. Six primary antibodies were used: three of them were directed to different splice variants of the NR1 subunit, one antibody was able to bind both to NR2A and NR2B subunit and two of the antibodies were directed to NR2A and NR2B subunit respectively. In order to reveal different combinations between the subunits, double labeling studies were fulfilled. All the antibodies caused well expressed labeling in frog retina. The labels had punctate character, a sign for synaptic localization of receptors. Despite of the specific character of expression of each antibody, the labels were mainly located in both plexiform layers: the inner and the outer one. The NR2A subunit was also located in the retinal glia, the Müller cells. During the double labeling studies colocalizations of the NR1 subunit with NR2A or NR2B were demonstrated. The results obtained show that the NR1, NR2A and NR2B subunits of the NMDA receptor are well expressed in frog retina. They are involved in the glutamatergic neurotransmission from the photoreceptors to the second order retinal neurons, as well as from the bipolar cells to the third order retinal neurons. The possibility several subtypes of NMDA receptors to exist each of them involved with different function is discussed.