This study was conducted to evaluate the effects of combination of two herbs Peppermint and Thyme powder on broiler performance and carcass characteristics. This experiment was done in a completely randomized design using 300 one day-old broilers (Ross) with five treatments and three replicates. Treatments include control (without any additives; T1), 1% Peppermint and 0.5% of Thyme (T2), 1% Peppermint and 1% Thyme (T3), 2% Peppermint and 0.5 % Thyme (T4) and 2% Peppermint and 1% of Thyme (T5). Results showed that feed intake in whole period (42 d) was not affected by treatments (P>0.05), although in the period of 1 to 21 d, there was significant increase (P<0.05) in T2 in terms of daily feed intake. Average daily gain in 1-21d, 22-42d and in the entire period was not affected by treatment (P>0.05), although numerically the largest weight gain was found in T5. The lowest feed conversion ratio (FCR) was observed in T3 in total periods although FCR was not affected significantly in all three experimental periods (P>0.05). The results showed that carcass weight, thigh weight, wing weight, chest weight, neck weight and liver weight at the end of the period was significantly high in T5 (P<0.05). However, the back weight, gizzard weight, intestinal length and abdominal fat were not affected by treatments (P>0.05). The results showed that the use of T5 in poultry rations have a good impact on performance and carcass characteristics.