Background: Although intra-arterial chemoradiotherapy (CRT) followed by surgery has been the standard of care for patients with advanced maxillary sinus squamous cell carcinoma (MSSCC), concurrent intra-arterial chemotherapy and high-dose radiotherapy without surgery has emerged as a promising alternative. Objectives: This study aimed to evaluate the ability of intra-arterial CRT alone to increase the overall survival (OS) of patients with MSSCC. Patients and Methods: Forty patients with histologically confirmed MSSCC, who were treated at Tokyo Medical University Hospital (Tokyo, Japan) between February 1999 and June 2015, were enrolled in this study. Twenty-seven patients were treated with intra-arterial CRT (median dose of 60 Gy) without surgery (CRT group), whereas 13 patients were treated with neoadjuvant intra-arterial CRT (median dose of 40 Gy), followed by surgery (S group). The association of OS with age, performance status, T factor (mean tumor size according to the tumor-node-metastasis [TNM] grading system), N factor (mean lymph node involvement according to the TNM grading system), and treatment method was assessed. Results: The median follow-up duration was 36.0 months. There were no significant differences regarding the patients’ characteristics between the two groups. The treatment method was the only significant prognostic factor for OS. The five-year OS rates were 92% and 55% in the CRT and S groups, respectively (P = 0.01). Conclusion: The intra-arterial CRT (60 Gy) without surgery yielded improved survival outcomes in patients with advanced MSSCC as compared to the neoadjuvant intra-arterial CRT (40 Gy) followed by surgery.