Abstract: This experiment was conducted to assess the effects of incorporating roselle seed in ruminants feed. Crushed Roselle Seeds (CRS) meal was used at three levels (0, 15 and 25%), in three isocaloric, isonitrogenous diets (A, B and C, respectively). Thirty-six male lambs of Sudan desert sheep (Hamarri ecotype) were selected at average age of 4-5 months and average body weight of 21.8 kg. The lambs were randomly assigned to three treatments (12 animals each), each treatment was further subdivided into three groups of four animals (replicates). The lambs were fed on the experimental rations for 70 days. The study showed significant differences (p<0.05) among the different treatments for Average Final Body Weight Gain (AFBG), Average Total Weight Gain (ATG), Average Daily Feed Intake (ADFI) as percentage of live body weight, Feed Conversion Rate (FCR) and cost of 1 kg dry matter intake wihle there were no significant differences (p>0.05) among the different treatments for Average Initial Body Weight (AIW), average daily feed intake and Average Daily Weight Gain (ADG). According to the results, roselle seed meal had no adverse effects on ruminant’s performance; it maybe used up to 25% in lambs feeding with satisfactory results. In addition, roselle seed meal could be used as a source of protein for growing lambs and fattening of sheep instead of other oil seeds cakes during the dry seasons and the lack of other protein source.