The present study was carried out to determine the effect of dietary organic acid mixture supplementation (product Pro Git) on performance (body weight changes, egg production) and concentration of some blood serum parameters in laying hens ,,Silver Adler”. A total 41 week old 2800 laying hens which were allotted into 2 groups, each containing 1400 hens. The hens were fed with diets (17,5% CP% and 2720 Kcal). Supplemented with 0% (control group 1), and 0,3 %(group 2) of organic acid mixture – Pro Git (formic acid, propionic and lactic acids). The dietary organic acids modify live body weight in groups 2 when compared with control one. Organic acids supplementation significantly increased egg production by about 2,7% compared with the untreated group. The data revealed that linear increase of serum calcium and concentration of total serum protein. From the obtained data can be concluding that organic acid supplementation at level 0,3 % of laying hens diet improve live body weight, improve persistence of lay and from economical point of view we can concluded that organic acid addition (0,3 %) amazing increase the economical efficiency of layer production.