Thanks to a Fulbright grant, the author has been able to stay in two American medical libraries : Houston academy of medicine/Texas medical center library, in Houston (Texas), a large academic, instructional and research library, and the Michigan regional center library in Midland (Michigan), a small hospital library. These two libraries, as well as most American medical libraries have a wide opening period, day and night. For their purchases, they follow collection development plans. They have precise functioning rules and objectives ; they belong to networks. They facilitate access to medical information thanks to big means, relevant tools and an exacting well-trained staff who knows to remain near to the users. Patient information is never forgotten. Patronage - « The friends of the library » - is frequent and maintains a positive image of these libraries.