Abstract: One hundred and eighty one-day-old Arbor Acre (AA) male broiler chicks were randomly allocated into three groups with six replicates each. From 8 days old, the chicks were supplemented with different levels of CoQ₁₀, i.e. 0, 20, and 40 mg/kg, respectively. During day 15 to day 21, all chicks were exposed to low ambient temperature(15~18 ℃) to induce ascites. The results showed that, under the condition of this trial, no significant effects were observed on broiler chicks’ growth performance, but the sensitivity of broiler chicks to ascites was significantly decreased by CoQ₁₀ supplementation. The ascites mortality of CoQ₁₀ supplemented groups was much lower than that of the control and EOF was significantly decreased by CoQ₁₀ supplementation. There were no significant changes observed on PCV between the control and the treatments. RVP, PAP and ±dp/dtmax were not influenced by the treatments except that PADP on day 36 was significantly decreased by 40 mg/kg CoQ₁₀ supplementation (P≤0.05). AHI was significantly reduced by 40 mg/kg CoQ₁₀ supplementation (P≤0.05). The beneficial effect of CoQ₁₀ may be attributed to its benefit for development of cardiac myocytes and decreasing EOF.