The purpose of this study is to assess the usefulness of soluble vascular endothelial growth factor (VEGF) in the effusions of patients with malignant and tuberculous diseases. Using a sandwich enzyme-linked immunoadsorbent assay, VEGF concentration was measured in malignant (n=17) and tuberculous (n=11) pleural effusions. Pleural biopsy, cytology or microbiological methods were used to make final diagnoses. Adenosine deaminase (ADA) levels in tuberculous pleural effusions were significantly higher than those in malignant pleural effusions. The median level of VEGF in patients with malignant effusions (median, 2418 pg/mL; range, 97-62103 pg/mL) was significantly higher than tuberculous effusions (median, 994 pg/mL; range, 44-3552 pg/mL). There were no significant differences in pleural VEGF levels in patients with different histological types of lung cancer. The VEGF level was not correlated with ADA, lactate dehydrogenase and total protein levels of pleural fluid. In conclusion, pleural VEGF levels in patients with malignant effusions were significantly higher than tuberculous effusions, and the measurement of pleural VEGF is helpful in discriminating between malignant and tuberculous effusions. Further studies are needed to determine the clinical value of VEGF as a tumor marker and a prognostic factor.