The current conventional treatment for locally advanced rectal cancer with stage II or III is surgery following or followed by chemoradiotherapy (CRT), which improved local control and overall survival when compared with surgery alone. Recently, a prospective randomized study with a large sample size and long-term follow-up reported that preoperative CRT resulted in improved local control and sphincter preservation, reduced toxicities, and comparative overall survival when compared with postoperative CRT. However, diagnostic imaging for accurate stage should be applied. In addition, chemotherapeutic regimen, schedule for radiation therapy, and timing of surgery should be also optimized in order to maximize the effect of preoperative CRT.