An inflatable, adjustable gastric band includes a flexible, hollow, resilient band and a flexible inflation tube connected to the band and complementary closing means that are capable of mutually engaging so as to lock a ring in a closed position. The ring formed by bringing the distal end and the proximal end of the band together into a slipknot. The hollow band has, in an inoperative position, a preformed curved portion which is extended, by a substantially rectilinear portion, from the proximal end area thereof to the free distal end of the band. The substantially rectilinear portion being suitable for facilitating the insertion of the proximal end of the tube through the loop(s) of the band, and in that the hollow band has, on the outer wall thereof, two loops, said loops being arranged on the substantially rectilinear portion of the hollow band.