The GENEBU Project is an open, observational survey evaluating home nebulizer practices in Italy. It consecutively included patients who were referred to one of the 27 participating chest clinics from May to December 1999 and who had been using a home nebulizer in the previous six months. The information source was a self-administered questionnaire compiled by the enrolled subjects. We collected 1257 questionnaires. The nebulizer equipment was heterogeneous, with at least 92 different models. Jet nebulizers were 90% of the total; 53% of these had a glass reservoir. Almost 80% of the patients selected the nebulizer themselves without any medical advice. In addition, most patients (> 80%) did not receive information on both the interface system and the optimal fill volume of the nebulizer. Corticosteroid nebulisation was widespread (74%), for both occasional and regular daily use, for both acute and chronic diseases from upper to lower airways. Beta 2-agonist (55%), anticholinergic (37%), mucolytic (32%) drugs were also often nebulised. More than 90% of patients mixed some active drugs. We conclude that the nebulizer equipment for home aerosol therapy was very heterogeneous and, probably, not always utilised at its best in Italy. The mixing of drugs and the widespread use of corticosteroids were peculiarities of home nebulizer therapy in Italy.