BACKGROUND Subcarinal node metastasis is common in patients with esophageal cancer. Some scholars have suggested that subcarinal nodes might not need to be sampled or dissected in patients with superficial squamous cell carcinoma of the thoracic esophagus. This research investigated the frequency of subcarinal node metastasis in patients with esophageal squamous cell carcinoma, identified the factors correlated to subcarinal node metastasis, and evaluated the clinical relevance of subcarinal node metastasis in thoracic esophageal squamous cell carcinoma. METHODS We retrospectively analyzed the clinical data of 1,812 consecutive patients with thoracic esophageal squamous cell carcinoma who underwent esophagectomy in the Cancer Center of Sun Yat-sen University. The surgical procedures included the left transthoracic procedure, Ivor-Lewis approach, and the cervical-thoracoabdominal procedure. RESULTS The frequency of subcarinal node metastasis was 10.0%. The univariate and multivariate analysis showed that longer tumor length, higher pathologic T stage, lower histologic grade, and positive lymph node metastases of other groups were associated with a higher frequency of subcarinal node metastasis (all p<0.05). Patients with solitary subcarinal node metastasis had a significantly lower 5-year cumulative survival rate than those with solitary paraesophageal node metastasis (25.3% vs 39.6%, p<0.05). CONCLUSIONS Longer tumor length, higher pathologic T stage, lower histologic grade, and positive lymph node metastases of other groups are associated with a higher frequency of subcarinal node metastasis. Subcarinal node metastasis indicates worse prognosis of patients with thoracic esophageal squamous cell carcinoma compared with paraesophageal node metastasis.