The effect of using sesame seeds (SS) at differentilevels in rationsiof lactatingigoats on theiriperformance forimilk production andifeed conversion efficiencyiwas studied. Fifteen lactatingiZaraibi goats withiaverage bodyiweight of 41.09 kg wereidivided randomlyiinto three equaligroups (5 in each group). Theicontrol group (G₁) was fedia ration consisting of concentrateifeed mixture and Berseemihay (50: 50 %) accordingito NRC (1981) allowances of dairy goats. Sesameiseeds were used to replace 10 and 20% oficoncentrate protein for groups G₂ and G₃, respectively. Theiexperimental period for the tested rationsilasted for 16 weeks. The obtained dataiindicated that the averageifeed intake (as dry matter) generallyireduced as a result to replacing of CFM withiSS in the rations. Concerningiblood profile, the obtainediresults indicated thatiboth treatments G₂ and G₃ positivelyiand significantly affectedisome hematological parametersisuch as hemoglobin (Hb) and meanicorpuscular hemoglobin concentration (MCHC %). Moreover, serumicholesterol and activity of enzymesiwere decreased withiincreasing level of sesame seedsiin goats' rations and the differencesiwere significant in enzyme activityionly. But, the effect of tested rationion other biochemical and physiological parameters was notisignificant. Concerning milkiproduction, the resultsiindicated that the average milkiyield was significantlyibetter with G₂ and G₃ (1.523 and 1.491 kg/h/d) compared withiG₁ (1.381 kg/h/d). Moreover, fat percentageiwas significantly higher as airesult to using of sesameiseeds in rations. But, theieffect of testedirations on other milkiconstituents and milk quality parametersiwas not significant. Theifeed conversion efficiency, basedion DM and CP was betteriwith G₂ (0.98 and 0.140, respectively) then G₃ (1.00 and 0.143, respectively) and lastlyiG₁ (1.09 and 0.154, respectively). Iniaddition, the economicireturn was noticeably higher by 15.25 and 18.64% withisesame seeds rations (G₂ and G₃, respectively) comparediwith the control. Accordingly, iticould be concluded that theiuse of sesame seeds to replace upito 20% of CFM has a great effection the economics of milkiproduction of lactating Zaraibi goats.