The aim of the present study was to evaluate the implementation of the 2003 Dutch guideline on the diagnosis and treatment of malignant pleural effusions, and the potential effect of the implementation on the clinical outcome of pleurodesis.All patients with malignant pleural effusion who had a pleural drain placed with the intention of performing pleurodesis were registered prospectively in four centres. Details of the procedure and fluid recurrence and survival data were noted.Patients with a proven malignancy (n5100) were entered into the registration database. Diagnostic guideline recommendations were followed in 60-70% of the patients. Surprisingly, pleurodesis was performed in only 75% of the patients, mainly due to the presence of a trapped lung. All pleurodeses were performed using talc, according to the guideline. Follow-up revealed fluid recurrence in 27 (36%) patients after a mean follow-up of 17 days (range 2-285 days); 14 patients with successful pleurodesis died with a median survival of 61 days (range 13-174 days). Systemic treatment following pleurodesis and good apposition of the pleural surfaces during drainage were good prognostic factors.Despite reasonable-to-good adherence to the guideline, the number of successful pleurodeses was low. Better predictors of a good pleurodesis outcome are needed.