We describe our experience using an implantable Port-A-Cath access system for intrapleural administration of gamma-interferon (gamma-IFN) in malignant mesothelioma patients. Twenty nine patients, with histologically proven malignant mesotheliomas were included in this study. To avoid complications the device was implanted in a subcutaneous pocket, and the catheter was connected via a tunnel. Also, a suction drain was installed in the pocket after placement. This procedure greatly reduced the high infection rate (64%) encountered with conventional open chest tubes. Patients' tolerance was excellent and maintenance minimal. In our opinion, the Port-A-Cath system is the most suitable device for intra-cavitary long-term therapy of malignant pleural effusions.