Background: New therapies have emerged in the treatment of pulmonary alveolar proteinosis (PAP) and, therefore, there is a real need to evaluate the efficacy of whole-lung lavage (WLL) in this rare disease. Objectives: The aim of this study was to assess the efficacy of WLL in patients with PAP. Methods: We included 33 patients from 12 centers, which are members of the French-Speaking Thoracic Endoscopy Group, for analysis. Data collection concerned patients and disease characteristics, pulmonary function tests (PFTs) and technical information on the procedure. Results: The median age of the patients was 44 years (range 13-77). There were 23 (71.9%) patients with respiratory insufficiency at presentation. All patients underwent WLL by general anesthesia and selective lung ventilation, except 1 who underwent awake flexible bronchoscopy. We noted differences in the technique, as 12 (36.36%) patients had percussion during the procedure and only 4 (12.1%) patients underwent 2-lung lavage during 1 anesthesia. A median of 12 L was used to perform WLL (1.0-40 L). Complications occurred in 11 (33.3%) patients, and 18 (56.25%) of them relapsed in a median period of 16.9 months. No significant changes were found in any PFT parameters studied, except for PaO2, which was significantly improved by 6.375 mm Hg (p = 0.0213) after the procedure compared to before. Conclusions: Although the application of the WLL technique was variable, overall, it significantly improved patients' short-term respiratory condition by improving PaO2. However, a long-term effect needs to be confirmed, as many of our patients relapsed.