Background : The balances of the proteinases and antiproteinases system have been implicated in the pathogenesis of various exudative pleural effusions. The aim of this study was to examine the matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of metalloproteinase-1 (TIMP-1) levels in exudative pleural effusions. Methods : The study included 33 tuberculous effusions, 17 malignant, and 5 transudates. The pleural levels of MMP-1 and TIMP-1 were determined using a commercially available ELISA assay. Results : The group of tuberculous effusions showed higher pleural MMP-1 levels than the malignant and transudates. The pleural TIMP-1 levels of the tuberculous and malignant effusions were higher than the transudates. Conclusion : Elevated pleural MMP-1 and TIMP-1 levels were found in tuberculous effusions.