The present invention is directed to a catheter clamp that is affixable to a patient's skin to hold a catheter in position while in use within a patient's body. In one embodiment, the clamp has a base adapted to be removably adhered to the patient's skin, two clamp members supported on the base and defining a region therebetween to receive the catheter body, the clamp members being adapted to move between an open position and a closed position, and locking means for releasably locking said clamp members in said closed position to hold the catheter body in a generally fixed position relative to said clamp. In another embodiment, the clamp includes a base adapted to be removably adhered to the patient's skin, two clamp members supported on the base and defining a space therebetween to receive the catheter body, the clamp members being adapted to move between an open position and a closed position, and an elongated release tab extending between the two clamp members and configured to releasably lock the clamp member around the catheter body. The two clamp members may be pivotably coupled to each other and the tab may be pivotably attached on one of the clamp members.