This invention provides surgical instruments having improved lockout mechanisms. The surgical instruments are of the type which have an operating mechanism for repeatedly performing a surgical procedure and a control mechanism for manipulating the instrument between a neutral position and a ready position for performing the surgical procedure. The instruments comprise a passive lockout assembly and an active lockout assembly. The passive lockout assembly includes a key which is operatively connected to the control mechanism. The key immobilizes the operating mechanism unless the instrument is in the ready position. The active lockout assembly includes a plunger operatively connected to a manually operable switch. The plunger immobilizes the operating mechanism unless the switch is operated and reengages the operating mechanism each time the instrument is used. Each time the instrument is used to perform the surgical operation, therefore, the instrument of the instrument must be in the ready position and the active lockout switch must be operated. Otherwise, the operating mechanism of the instrument is immobilized by one or both of the passive and active lockout assemblies.