Abstract: In the near future, the part of energy dissipation due to information loss in irreversible computation will become a serious issue in VLSI chips. A Quantum-dot Cellular Automata (QCA) is anemerging nanotechnology which facilitates reversible computing. It’s a new computing paradigm with applications in extremely low energy dissipation. In this study reversible full adder-subtractor is proposed. For evaluating the functionality and energy dissipation QCA Designer and QCAPro tools are used. Proposed design is implemented in multi–layer in QCA designertool. It improves 78% of cell count compared to the existing QCA-based reversible full adder-subtractor. QCAPro tool demonstrates the efficiency of leakage and switching energy improvements.