Selenium is an important element for human and animal nutrition and deficiency problems of it in our soils is likely. The deficiency and toxicity range of selenium is very narrow and can cause nutritional problems for human and animal health. Plants can accumulate various amounts of Se in their tissues. The objective of this study was to examine selenium and cow manure treatments effects on crop yield and selenium concentration and uptake of plants. The study was carried out in a greenhouse using a factorial experiment design in a completely randomized plot with three replications. The treatments were five levels of 0, 5, 10, 20 and 40 g ha -1 of selenium and 0 and 100 Mg ha -1 of cow manure. The soil used was from Lavark experimental station and test plants were Alfalfa ( Medicago sativa ) and Fescue ( Festuca arundinacea ). The plants were harvested in three cuts, each cut when the height reached 20 cm. The harvested samples were oven dried, weighed and selenium concentrations were measured in them. Crop yields and plant growth were affected by the cow manure treatments in all the cuts, but selenium concentration of the plant tissues and selenium uptake of plants diminished. Alfalfa had the highest yield in all the treatments. Selenium treatments had no effects on the crop yields and plant growth. Selenium concentration and plant uptake increased with increasing selenium treatments in all of the cuts. The results of this study showed that in absence of organic matter content, selenium fertilizer could effectively increase the selenium concentration and plant uptake of selenium.