In this study, the incidence of thyroid cartilage invasion in early-stage laryngeal tumors involving anterior commissure was assessed. Medical charts and pathology reports of 62 patients who underwent supracricoid partial laryngectomy as the primary treatment of early-staged laryngeal squamous cell carcinoma were retrospectively reviewed. Patients were divided into two groups according to the macroscopic examination of the surgical specimen: tumors limited to the glottis with the involvement of anterior commissure (TLG); tumors invading both supraglottis and glottis with the involvement of anterior commissure (TISG). Thirty-seven of the cases were classified as TLG group (59.7 %) and the remaining 25 of them were classified as TISG group (40.3 %). Thyroid cartilage invasion was observed totally in ten patients (16.1 %), as macroscopic invasion in two cases and microinvasion in eight patients. Only two were in the TLG group (cartilage invasion rate of 5.4 %), the remaining eight were in the TISG group (cartilage invasion rate of 32 %). Thyroid cartilage invasion rate of TISG group was significantly higher than that of TLG group (p = 0.011, p < 0.05). Tumors limited to the glottis with AC involvement may be more suitable for endoscopic resection; on the contrary, tumors with vertical extension invading both AC and supraglottis should be evaluated more suspiciously due to high rate of thyroid cartilage invasion, which may still necessitate external laryngectomy techniques.