IN ORDER TO INVESTIGATE SELENIUM (SE) CONCENTRATION OF THE TOPS OF SAINFOIN ( ONOBRYCHIS VICIFOLIA ) AND Bromus (Bromus INERMIS) FERTILIZED WITH SODIUM SELENITE, A POT EXPERIMENT WAS CONDUCTED IN A GREENHOUSE LOCATED AT THE COLLEGE OF AGRICULTURE, ISFAHAN UNIVERSITY OF TECHNOLOGY, ISFAHAN, IRAN. SELENIUM DEFICIENT SOILS WERE BROUGHT FROM COLLEGE OF AGRICULTURE EXPERIMENT STATION OF LAVARK NAJAFABAD. SOILS WERE AIR- DRIED, CRUSHED AND SIEVED THROUGH A 2 MM SIEVE, AND AMENDED WITH SODIUM SELENITE MIXED WITH AMMONIUM PHOSPHATE FERTILIZER BEFORE APPLYING TO THE EXPERIMENTAL POTS. EXPERIMENTAL POTS WERE DESIGNED AS FACTOREAL SPLIT WITH TIME. SELENIUM TREATMENTS W ERE 0, 15, 30, 60 AND 120 KG SE PER HA; EACH TREATMENT WAS TRIPLICATED. POTS WERE IRRIGATED WHEN NEEDED WITH AVAILABLE IRRIGATION WATER WHICH WAS EXTREMELY LOW IN SE. 0.5 G OF GROUND SAMPLES WERE WET DIGESTED. SAMPLES WERE ANALYZED FOR SE CONCENTRATION USING ATMONIC ABSORPTION SPECTROPHOTOMETRY. THE RESULTS OF THIS STUDY SUGGEST THAT APPLICATION OF 30 G HA-1 SE IN BromusE AND 60 G HA-1 OF SE IN SAINFOIN IN THE FORM OF SODIUM SELENITE FERTILIZER WERE SUFFICIENT TO PROVID RECOMMENDED CONCENTRATION OF SE IN THE STUDIED FORAGE CROPS TO COVER THE NUTRITIONAL NEED OF ANIMALS.