Abstract: This experiment was conducted to evaluate the effects of supplementing the diet of laying hens with a combination of Zn and Mn on performance traits and broken eggs in a Completely Randomized Design with a 4x4 (16 treatment) factorial arrangement. Three hundred and twenty, 28 weeks old white leghorn laying hens, strain Hy-Line W36 were divided into 64 groups, five hens per group and each four groups were assigned to one of the 16 experimental diets. Sixteen experimental diets contained a corn-soybean basal diet containing 50 mg kg-1 Zn and 30 mg kg-1 Mn supplemented with 0-0, 0-30, 0-60, 0-90, 50-0, 50-30, 50-60, 50-90, 100-0, 100-30, 100-60, 100-90, 150-0, 150-30, 150-60 and 150-90 mg kg-1 of Zn and Mn, respectively. The results indicated that Mn and Zn in combination, Mn alone and age had not any effect on egg output, feed consumption and feed conversion ratio. Mn and Zn alone and in combination had a significant (p<0.05, p<0.05 and p<0.01, respectively) effect on broken eggs. Different levels of Zn had significant (p<0.05) effect on egg production, without any effect on egg output, feed consumption and feed conversion ratio. Age of birds had significant (p<0.05) effect on feed consumption but did not affect egg output, egg production and feed conversion ratio.