Introduction: Pulmonary adenocarcinoma is a major cause of mortality worldwide. The majority of patients present with advanced stage disease, and minimally invasive procedures are desirable for diagnosis and treatment plans. Herein, we report our experience with percutaneous/transthoracic needle aspiration (TT-NA) in the cytologic diagnosis of pulmonary adenocarcinoma. Material and Methods: After institutional review board approval, the cytopathology electronic data system was searched for all consecutive TT-NA of the lung masses from January 2011 to November 2015. Patients’ medical records were reviewed and cytologic materials were evaluated. Results: A total of 151 specimens were identified, with a mean age of 62.8 years; 62.9% of the patients had a prior history of malignancy. Carcinoma/adenocarcinoma was the most common (80%) diagnosis. The targeted lesions were predominantly located in the lung (56.3%, 81/151) and pleural based (27.8%, 42/151). The mean size of the lesions was 3.6 cm. Cytology specimens were adequate in 70.9% of the cases, while 72.8% (110/151) of the cases also had concurrent core biopsy. A malignant diagnosis was rendered in the majority of the cases (64.9%). In 71% of the cases, immunohistochemistry/histochemistry studies were successfully performed. Molecular/genetic studies were requested in 80% of the cases and had adequate material. Complications of the procedure were seen in 9.9% of the patients including pneumothorax (7.9%) and hemoptysis (1.9%). Conclusion: TT-NA is a relatively safe and reliable technique in the assessment of pulmonary lesions.