INTRODUCTION: The objective of the present study was to evaluate the use of a single lumen 16 G central venous catheter for the drainage of uncomplicated pleural effusions in intensive care unit patients. METHODS: A prospective observational study was performed in two intensive care units of university-affiliated hospitals. The study involved 10 intensive care unit patients with non-loculated large effusions. A 16 G central venous catheter was inserted at the bedside without ultrasound guidance using the Seldinger technique. The catheter was left in situ until radiological resolution of the effusion. RESULTS: Fifteen sets of data were obtained. The mean and standard deviation of the volumes drained at 1, 6 and 24 hours post catheter insertion were 454 +/- 241 ml, 756 +/- 403 ml and 1010 +/- 469 ml, respectively. The largest volume drained in a single patient was 6030 ml over 11 days. The longest period for which the catheter remained in situ without evidence of infection was 14 days. There were no instances of pneumothorax, hemothorax, re-expansion pulmonary edema and catheter blockage/ disconnections. CONCLUSIONS: The use of an indwelling 16 G central venous catheter is efficacious in draining uncomplicated large pleural effusions. It is well tolerated by patients and is associated with minimal complications. It has the potential to avoid repeated thoracentesis or the use of large-bore chest tubes.