Two experiments were done in this experiment to evaluate the comparison of the use of chromium chloride (Cr) as CrCl3 and L-carnitine, either alone or in combination with vitamin C, during heat stress in the summer on the egg performance and egg quality. In each experiment, one hundred and twenty individual of a 28-week golden Montazah-layer hen, according to a completely randomized design were divided into four groups, each group had three replicates, and each replicate had 10 laying hens.  Layers were housed in cages (one bird/cage) and at high ambient temperatures (day and night cyclic temperatures ranged from 28 to 42°C) throughout the 12-week trial period. Layers have been fed by commercial classes throughout the experiment with access to feed and water. In1st experiment, the treatments were Group 1 = control, (0 additives), group 2 = vitamin C, (250 mg/kg feed), group 3 = Cr, (400 mg/kg feed), group 4 =  (Cr 400 mg/kg feed + vitamin C 250 mg/kg  feed). In 2nd experiment were Group 1 = control, (0 additives), group 2 = vitamin C, (250 mg/kg feed),, group 3 = L-carnitine, (100 mg feed), group 4 = (L-carnitine 100 mg feed + vitamin C 250 mg/kg feed), The results indicated that groups supplementation of 400 mg (Cr) and 100 mg L-carnitine either alone or combination with 250 mg vitamin C /kg diet improving feed conversation, egg number, egg mass and egg production percentage compared with control group or vitamin C alone, while egg weight increased by using L-carnitine with vitamin C compared with other groups. Also results demonstrated feeding supplemental  (Cr) and L-carnitine, either alone or in combination with vitamin C had no effect on egg length, egg diameter, egg shell thickness, egg shell weight but its increased  albumen height (p < 0.01). It can be concluded that supplementation of 400 mg (Cr/kg feed) and 100 mg L-carnitine /kg feed either alone or combination with vitamin C 250 mg /kg diet, improved production performance for Golden Montazah hens at 29- 40 weeks of age during the summer season.