A hose clamp, preferably for the closing of catheter extensions, has an integral plastic body extending in an elongate manner with two arms which are resiliently connected to one another at the ends and which each form a projection such that they are disposed opposite one another in the closed state of the hose clamp. The arms can be hooked with one another in the closed state with openings being provided at the front and rear ends thereof for the reception of a hose. The hose clamp generally has the shape of a cylinder with cut-off sides which taper conically at both sides toward the ends of the clamp, with the ends being adapted to the circular shape of a hose is received therein.