The effect of salinity on the activity of glutamine synthetase (GS EC 6.3.1.2.) and glutamate dehydrogenase (NAD(P)H-GDH EC 1.4.1.2-4) in shoots and roots of triticale seedlings was investigated. Stressed plants were cultured hydroponically on the 100 mM NaCl-enriched medium for 7 days and the physiological responses were measured. Apart from changes in morphology of plants, alterations in GS and NAD(P)H-GDH activity were reported. GS activity in roots of stressed plants grew slightly and in shoots it decreased by approx. 30% as compared to control plants. In shoots of both control and stressed plants two GS isoforms were detected: cytoplasmic (GS₁) and chloroplastic (GS₂). A drop in total GS activity in shoots of NaCl-treated plants was due to the drop in activity of GS₂ isoform. The activity of GS₁ grew slightly under saline stress. After staining of gels for GDH activity, no changes in isoforms were noted as compared with the control plants.