Abstract: Taking advantage of medicinal plants is developing in the poultry industry as an easy, economical and beneficial way in order to elevate the poultry’s out come. This experiment was conducted to find out the effects of Melissa officinalis L., Tanacetum balsamita L. and Ziziphora clinopodioides L. on performance, egg quality, blood biochemical and immunity parameters of laying hens. This study was carried out with 288 of Hy-line (W36) hens in 8 treatment groups and 3 repetitions for each group. The groups were (1) Control group (2) (2% Melissa officinalis L., 3) 2% Tanacetum balsamita L. (4) 2% Ziziphora clinopodioides L. (5) 1% Melissa officinalis L. and 1% Tanacetum balsamita L. (6) 1% Melissa officinalis L. and 1% Ziziphora clinopodioides (7) 1% Tanacetum balsamita L. and 1% Ziziphora clinopodioides and (8) 0.67% of each three medicinal plants. According to the results, there were significant effects of these plants using on performance, egg quality and blood biochemical parameters of hens (p<0.05). The highest percentage of egg production, the lowest feed conversion ratio, the highest weight and the highest index of yolk were seen in the 6th group. The highest egg weight was in the 5th group and the highest weight of white was in the 3rd group. Also these plants improved the immune system and blood biochemical parameters of laying hens. According to the results of this study, these three herbs can remarkably boost the performance and immunity of laying hens.