Despite a lack of robust data regarding their efficacy, oral antibiotics and steroids remain two of the most common treatments for chronic rhinosinusitis without nasal polyps (CRSsNP). We sought to objectively compare the efficacy of antibiotics and steroids, independently and in combination, for the initial treatment of CRSsNP. To that end, we conducted a retrospective chart review of 100 patients-51 men and 49 women, age 20 to 85 years (mean: 50)-who were treated for CRSsNP from January 2010 through January 2015. Of this group, 17 patients were treated with an antibiotic only, 28 with a steroid only, and 55 with both agents. All patients underwent computed tomography (CT) before and after treatment, and we compared the three groups' pre- and post-treatment Lund-Mackay CT scores, symptom scores, and rates of surgery. The average time between the pre- and post-treatment visits was 4.4 weeks. The mean Lund-Mackay CT score for the entire study population was significantly lower after treatment than at baseline (6.3 vs. 9.1; p < 0.001); however, there were no significant differences among the three groups in either pre- or post-treatment scores. Symptom scores were significantly better in the combination therapy group than in the two monotherapy groups (p < 0.001). In all, 40 of the 100 patients underwent surgery; the difference in surgery rates among the three groups was not statistically significant (p = 0.884). Surgery was performed on 9 of the 52 (17.3%) patients who either were followed for at least 1 year or who had had surgery within the first year postoperatively; again, there were no significant differences among the three groups (p = 0.578). We conclude that although the Lund-Mackay CT scores decreased significantly in the antibiotic, steroid, and combination therapy groups, no one regimen was superior to any other for treating CRSsNP in our study.