Background: Recent publications have confirmed that 70% of hospitalized adults with uncomplicated community-acquired pneumonia and health-care-associated pneumonia are prescribed a duration therapy that exceeds current guideline recommendations. Objective: The primary objective is to evaluate the relationship between antibiotic duration and all-cause 30-day readmission rates. Secondary outcomes include pneumonia-specific 30-day readmission rate and identification of risk factors for readmission. Methods: Patients aged ≥18 years with a primary diagnosis of pneumonia from January 1, 2016, to December 31, 2016, were included in this single-center, retrospective cohort study. Patients were categorized by antibiotic therapy duration of ≤7 days (n = 139) or >7 days (n = 286), and outcomes were analyzed in both bivariate and multivariate models. A multivariate logistic regression was used to assess the relationship between all-cause 30-day readmission and antibiotic days. Results: Baseline characteristics were not significantly different between the 2 groups. All-cause 30-day readmission rates were 15.8% and 15.5% for patients who received ≤7 days versus >7 days of antibiotics, respectively ( P = .95). Pneumonia-specific 30-day readmission occurred in 3.6% of patients who received antibiotics for ≤7 days compared to 3.5% of patients who received antibiotics for >7 days ( P = .95). Multivariate logistic regression showed no statistically significant association between readmission rate and antibiotic duration of >7 days. Statistically significant risk factors for readmission identified by logistic regression include ≥3 hospital admissions within the previous year, a hematocrit <30% at discharge, a history of chronic obstructive pulmonary disorder (COPD), and weight. Conclusion: The use of prolonged antibiotic therapy for the treatment of community-onset pneumonia was not associated with a decrease in all-cause or pneumonia-specific 30-day readmission rates.