Purpose: A tube thoracostomy is an invasive procedure that places patients at risk for complications. Tube thoracostomies are frequently performed by emergency medicine residents. Thus, the purpose of the study was to assess both the complication rate for tube thoracostomies performed by emergency medicine residents and the factors associated with these complications. Methods: A retrospective chart review of all patients who had undergone a tube thoracostomy performed by emergency medicine residents between January 2008 and February 2009 was conducted at a university hospital. Complications were divided into major and minor complications and into immediate and delayed complications. Complications requiring corrective surgical intervention, requiring the administration of blood products, or involving situations requiring intravenous antibiotics were defined as major. Complications that were detected within 2 hours were defined as immediate. Results: Tube thoracostomies were performed in 189 patients, and 70 patients(37%) experienced some complications. Most complications were immediate and minor. In multiple logistic regressions, BMI, hypotension and resident seniority were significantly associated with complications. Conclusion: The prevalence of complications was similar to these in previous reports on the complications of a tube thoracostomy. Most complications from tube thoracostomies performed by emergency medicine residents were immediate and minor complications. Thus, emergency medicine residents should be allowed to perform closed tube thoracostomies instead of thoracic surgeons.