Floating-Harbor syndrome is a rare congenital disorder characterized by specific facial features, short stature associated with significantly delayed bone age and language impairment. Although language delay is a cardinal manifestation of this syndrome, few reports describe the specific language difficulties of these patients, particularly the development of language abilities in the long run. This paper reports on an Italian boy with Floating-Harbor syndrome and discusses his language evaluation at presentation (age 48 months) and development and progress of his language abilities after 4 years of rehabilitation treatment. At presentation he exhibited borderline mental retardation, with verbal abilities lower than performance abilities. He showed significant impairment of both expressive and receptive language, and also exhibited phonologic and articulations problems that lowered speech intelligibility. Neuropsychological assessment revealed cognitive problems. After speech-language rehabilitation treatment, he achieved significant improvement in language function. Learning outcomes: The reader will learn about (1) the distinctive clinical characteristics and (2) the speech-language abilities and their development after speech-language therapy in Floating-Harbor syndrome. (Contains 5 tables.)