A catheter including one or more bidirectional valves is provided. The catheter includes a tubular body having proximal and distal ends, and inner and outer surfaces, and at least one valve formed near the distal end of the tubular body. The valve includes a deformation portion that defines a slit that is openable and closable. The openable/closable slit communicates from the inner surface to the outer surface of the tubular body, wherein the distance between the inner surface and the outer surface of the tubular body progressively becomes thinner approaching the openable/closable slit within the deformation portion.