Background: Neoadjuvant chemoradiation represents the current standard of care for locally advanced rectal cancer prior to surgical resection. Traditionally, 3D conformal radiation therapy (3D CRT) was used in this setting. With advancing technology, intensity modulated radiation therapy (IMRT) was developed with the goal of delivering a more conformal radiation dose, with the potential for reduced toxicity providing a potential advantage across many disease sites. We sought to use the national cancer database (NCDB) to examine trends and predictors for IMRT use in rectal cancer. Methods: We queried the NCDB from 2004-2015 for patients with rectal adenocarcinoma treated with neoadjuvant concurrent chemoradiation to a standard doses (50.4-54Gy) followed by surgical resection. Odds ratios were used to determine predictors of IMRT use. Univariable and multivariable cox regressions were used to determine potential predictors of overall survival (OS). Propensity matching was used to account for any indication bias. Results: We identified 21,490 patients satisfying eligibility criteria, of which 3,131 were treated with IMRT. IMRT use increased from 1% in 2004 to 22% in 2014. Predictors for IMRT use included increased N stage, more recent treatment year, treatment at an academic facility, increased income, and higher educational level. On multivariable analysis including propensity score male gender, increased distance to facility, higher comorbidity score, IMRT technique, government insurance, African American race, and non-metro location were predictive of worse OS. Of note, the complete response rate at time of surgery was 28% with non-IMRT and 21% with IMRT. Conclusions: IMRT use has steadily increased in the treatment of rectal cancer, but still remains only a fraction of overall treatment technique. IMRT use correlated with worse survival likely due to utilization in higher stages and patients with worse disease features.