Effect of intercropping of lentil with barley was studied at Department of Agronomy, University of Zabol, on a sandy loam soil during autumn 2011 growing season in order to determine biological and economical yield of barley (Hordeum vulgar L.) mixed with lentil (Lens culinaris L) cultivar mono cropped or intercropped in replacement series design. The treatments were compared in a randomized completely block design (RCBD) with five levels of row intercropping that was included: sole barley (6 row barley), 4 row barely + 2 row lentil, 4 row lentil + 2 row barley, 3 row barley + 3 row lentil and sole lentil (6 row lentil) in three replication. Results indicated that intercropping system affected many characteristics such as plant height, biological and economical yield. Intercropped barley with lentil was far more effective than mono crop barley to produce yield and land equivalent ratio. The highest of LER for economical yield was obtained at 3 row barley + 3 row lentil (2.61) and the least of LER was obtained by 2 row barley + 4 row lentils. The results were shown that for get maximum production barely should be sown as an intercrop to lentil and the best treatment was It 3 row barley + 3 row lentils in sistan region. Thus It can be concluded that mixture were advantageous compared to both sole crops of barley and lentil.