Abstract: A lockout device (20, 120, 220) for locking a valve (22, 122, 222) into its closed position. In a first embodiment, a lockout device (20) is adapted for use with a valve (22) having a lever-type handle (24) and a valve body (28). Accordingly, the first embodiment includes a generally cup-shaped member (36) having an elongate close-ended slot (46) for receiving the lever-type handle. In a second embodiment, a lockout device (120) is adapted for use with a valve (122) that includes a handle (124) having raised indicia (174) on its upper surface (176). Accordingly, the second embodiment includes a generally cup-shaped member (136) that includes an end wall (140) having a recess (182) for receiving the raised indicia only when the valve is in its fully-closed position. A third embodiment of a lockout device (220) comprises a base (272) and a locking member (274) telescopically engaging the base. The locking member may alternately be positioned in a retracted, unlocked position and an extended, locked position.