To investigate the effect of dietary inorganic and organic sources of Zinc, Copper and Manganese on production performance, egg quality and immune responses in old laying hens, two separate complete randomized design experiments were conducted with Hy-line W-36 layers in 48 weeks-old. The birds were subjected to a 10-d adaptation period and main trial stage lasted 70 days. In the first trial, a total of 240 hens were assigned to 8 dietary treatments with 5 replicates of six birds each in a 2×2×2 factorial arrangement contains two levels of 0 and 70 mg/kg of zinc (from ZnSO 4 .H 2 O), two levels of 0 and 80 mg/kg of manganese (from MnSO 4 .H 2 O) and two levels of copper (from CuSO 4 .5H 2 O) to evaluate the effect of inorganic sources of zinc, copper and manganese on performance and egg quality factors. The results showed that dietary inorganic sources of zinc, copper and manganese during first 35 d caused significant (P 0.05) increase in egg production and egg ma and the effect of Zn×Mn×Cu on egg production(P 0.05) in this period were significant. Also, egg shell strengths and thickness in first 35 d was affected by all inorganic sources. In first 35 d, the effect of copper and manganese in egg shell strength (P 0.05) and manganese in egg shell thickness (P 0.05) were significant. In Zn×Cu and Zn×Mn treatments immunity responses against sheep red blood cell (SRBC) were increased (P 0.01) significantly post first injection and in Cu (P 0.05) and Zn (P 0.001) treatment Newcastle antibody titer markedly improved both in 7 and 14 days post vaccine. Experiment 2 were performed with 240 laying hens that were allocated to 8 dietary treatments with 5 replicates of six birds each, in a 2×2×2 factorial arrangement with two levels of 0 and 70 mg/kg of zinc (from Zn-Met), two levels of 0 and 80 mg/kg of manganese (from Mn-Met) and two levels of copper (from Cu-Met) to evaluate the effect of inorganic sources of zinc, copper and manganese on performance and egg quality factors. The egg production were affected by zinc supplementation in second 35 d (P 0.01), and in all 70 d experimental period egg production and FCR (P 0.05) were affected significantly. Organic sources of copper (P 0.05), zinc (P 0.05) and manganese (P 0.01) cause increase in egg thickness in 5 th week of experiment. Also, the effect of Cu×Mn treatment in eggshell strength (P 0.05) were significant. Cu treatment in first week post Newcastle vaccine cause markedly (P 0.01) increase in antibody production. The effect of zinc treatment in first and second week post Newcastle disease vaccine in antibody production (P 0.001) were significant. In conclusion, the present finding indicate that, organic minerals, specially Zinc-Met, can improve some factor
