The present study was planned to investigate the extent of the protective effect of cinnamon against the possible damage effect of thermally oxidized palm oil on broiler chicks. A total number of 150 one d-old Cobb 500 broiler chicks were randomly divided into three treatment groups. The first group was served as control and fed the basal diet with tap water. While the 2^ndgroup fed the basal diet supplemented with 2g cinnamon/kg diet, the 3^rd group fed the basal diet supplemented with 5% thermally oxidized palm oil in combination with 2g cinnamon/kg diet. The experiment has lasted till chicks were 42 d old. Bodyweight, feed consumption, feed conversion ratio was estimated.  Estimation of the effect of different treatments on the PPAR-α gene expression, Estimation of the lipid profile in serum, Estimation of the cholesterol level in the liver tissue. Correlation between the cholesterol level in both serum and liver tissue and determination of oxidative stress markers in serum. The results showed that the addition of cinnamon increases body weight and feed consumption plus improving the feed conversion ratio. Cinnamon also causes a significant increase in the PPAR-α gene expression in liver tissue, decreases the cholesterol concentrations in serum and liver, decreases triglycerides in serum and decreases the oxidative stress markers.