Quantum Cellular Automata (QCA) is a transistor-less computation model that addresses the problem of device interconnection and density which holds the promise of high speed and fewer sizes compare to the Complementary Metal Oxide Semiconductor (CMOS) design. In this study, the design of 4-bit down asynchronous counter which is the fundamental block of the digital technology using new D-Flip Flops (D-FF) layouts is discussed. This D-FF is designed using majority gates. The FF clock inputs are not driven by the same clock and each FF output depends on the previous output. This design finds its application in nanotechnology fields including medical field to monitor the patient"s activity by utilizing timer based tools. The design of 4-bit down asynchronous counter is simulated in the QCA design tool.