Licorice is a leguminous and its root extract is used in industries of pharmacology. After extracting from the root, the remainder is called pulp. To determine nutritive value of the root pulp, its chemical composition and digestibility of DM, OM and energy were determined usingin vivo method. Alfalfa and wheat straw were replaced with licorice root pulp at the ratio of 0, 13.5, 20 and 26.5 percent. Diets were isocaloric and isonitrogenous and C: F ratio was 33.33: 66.66. To compare effects of different levels of root pulp on average daily gain and feed conversion ratio, 32 Kordi lambs were randomly assigned to four treatments. DM, CF, EE, ash, CF, NDF, ADF, ADL, Ca, P and GE of root pulp were 91.4, 8.05, 0.7, 9.4, 38.0, 67.7, 46.7, 20.4, 0.87, 0.23 % and 4.4 Mcal/kgDM, respectively. Digestibility of DM, OM, and energy were 37.43, 40.02 and 38.08% and after subtracting associative effects were 42.20, 40.09 and 42.63% respectively. Average daily gain of lambes from T0, T1, T2 and T3 was 212.08, 207.00, 213.39 and 220.75 g/d and variation was not significant (p>0.05). Feed conversion ratios for treatment 1 through 4 were 7.69, 7.58, 7.46 and 7.29 which no significant difference was observed among them (P>0.05). It seems that licorice root pulp could be replaced for some part of roughage (Strow) in similar rations without any adverse effect on performance of animal.