To assess the value of immediate cytologic evaluation (ICE) in mediastinal endoscopic ultrasound-guided transesophageal fine needle aspiration (EUS-FNA). Fifty eight patients with mediastinal lymphadenopathy underwent transesophageal EUS-FNA. Cellularity, number of needle passes and number of slides prepared were reviewed retrospectively. Of moderate to highly cellular passes, 75% were diagnostic. ICE had a 100% positive predictive value and 97% negative predictive value. ICE allowed a diagnosis in all cases. Calculated diagnostic accuracy was 70% if the procedure ended after a single specimen of at least moderate cellularity or after completion of 4 needle passes. Immediate cytologic evaluation of EUS-FNA specimens allowed a diagnosis in all cases and contributed to the utility of EUS-FNA as a diagnostic procedure for mediastinal adenopathy.