Abstract: A sliding door rotary latch system includes a handle assembly mounted on the sliding door adjacent its leading edge, a rotary latch assembly and locking mechanism mounted on the front post of the door frame cooperating with a strike bar on the handle assembly selectively to latch the sliding door in its fully closed position and a rear latch plate mounted on the back post of the door frame cooperating with the handle assembly selectively to latch the sliding door in its fully open position. The door mounted handle assembly includes an outer pivotal handle, an inner pivotal handle, and an inner actuation mechanism operative to allow either handle independently of the other to actuate either a pivotal front cam actuator arm or a rear pivotal latch independent of the other. Either handle may be held in its pivoted position toward the direction of sliding movement of the door during that sliding movement without adversely effecting the latching action when the door is either fully closed or opened.