This study was carried out to evaluate the effect of liquid smoke (LS) produced from beech sawdust and thyme essential oil (TEO) as natural antioxidants in chicken and turkey meatballs during frozen storage. The LS and TEO were added to chicken and turkey meatballs at levels of 1% and 0.1%, respectively, and storage at -18 ± 1°C for 6 months.  pH value, water holding capacity (WHC), total volatile nitrogen (TVN), thiobarbituricacid (TBA) value, peroxide values (PV), total phenolic compounds (TPC) and antioxidant activity (DPPH %) were determined. The results demonstrated that the addition of LS or TEO had a positive effect on storage stability and a little change in the physical properties, quality attributes, and significantly (p≤0.05) increased the values of total phenolic compounds and antioxidant activity of chicken and turkey meatballs during frozen storage compared to the control sample. The data revealed that the application of liquid smoke had decreased the value of TBA, TVN, and PV as well as increased shelf life and could be useful to achieve high stability of activity of chicken and turkey meatballs during storage and was better accepted compared to TEO and control.