We evaluated the efficacy of pleurodesis using OK-432 (Picibanil) for the treatment of pneumothorax associated with pulmonary lymphangioleiomyomatosis (LAM). Seven episodes of pneumothorax in five patients with LAM were treated with pleurodesis using OK-432. First, all patients underwent tube thoracostomy drainage. After drainage, 5 or 10 KE of OK-432 was administered via the tube. If incomplete lung expansion or a continuous air leak occurred, an additional 5 KE of OK-432 was administered. Of the five patients, two developed pneumothorax for the first time and three had a history of previous pneumothorax. The mean total dose of OK-432 administered was 13.6 KE, and the mean period of tube drainage was 11 days. The only recurrence of ipsilateral pneumothorax after OK-432 pleurodesis was observed seven years and eight months later in association with chronic respiratory failure in one patient. This patient was successfully treated with repeated pleurodesis using OK-432 during mechanical ventilation, and no recurrence has developed in the eight years since then. The main side effects of the procedure with OK-432 were fever and chest pain, which were well controlled by non-steroidal anti-inflammatory drugs. The study concluded that pleurodesis with OK-432 was an effective and safe treatment for intractable and recurrent pneumothorax associated with LAM.