There are many patient and institutional variables associated with a higher risk of rehospitalization within 30 days of an admission for community-acquired pneumonia. However, less is known regarding the impact of antibiotics. A retrospective cohort study of 271 patients was performed to determine whether, when controlling for known factors for readmission, the choice of antibiotic affects 30-day rehospitalization after an index admission of pneumonia. Multivariate logistic regression analysis was performed to determine correlation between antibiotic choice and readmission rates. Empiric tobramycin was associated with a 31.2% increased risk of readmission for any reason (P < 0.01). Empiric and treatment aztreonam were associated with a 13.7% and 13.5% increased risk of readmission with recurrent pneumonia, respectively (both P < 0.05). Further research evaluating these associations is warranted.