Abstract: A dual flush valve includes an outflow pipe, a lower seal, and an upwardly extending guide. A lower flush valve reciprocates on the guide between a lowered position sealing the lower seal and a full volume flush position unsealing the lower seal with respect to the outflow pipe. An upper flush valve reciprocates on the guide between a lower sealed position sealing the upper seal with respect to the lower flush valve, an intermediate partial volume flush position unsealing the upper seal and a higher full volume flush position unsealing the lower seal. An interconnecting lost motion member allows movement of the upper valve between the lower sealed position and the partial volume flush position without disturbing the lower valve, while transmitting additional upward movement of the upper valve to the lower valve to move the lower valve between the lowered position and the full volume flush position.