To determine whether the diagnostic yield of transbronchial needle aspiration (TBNA) improves over time and to obtain insights about factors influencing its performance, we reviewed our experience during a 3-yr period. After serial multifaceted educational interventions directed toward bronchoscopists and their technical staff, TBNA yield increased significantly from 21.4 to 47.6% (p < 0.001). More frequent and more detailed notations in bronchoscopy reports (p < 0.05), a lower frequency of cytopathology specimens contaminated by endobronchial material (p < 0.05), and higher yields in patients with small cell carcinoma (p < 0.01) suggested that bronchoscopists' TBNA proficiency had increased. More frequent diagnoses with small cell carcinoma and fewer cytologically unsatisfactory specimens (p < 0.01) suggested that education of bronchoscopy technicians, and use of a direct smear technique for specimen preparation also contributed to improved TBNA yield. Increased experience with TBNA and focused education regarding its performance can enhance the role of this procedure in diagnosis and staging of patients with lung cancer.