Abstract: Reversible computation is of major interest in low power design and nanotechnology-based systems. A reversible logic gate has the same number of inputs and outputs and a one-to-one correspondence between the inputs and the outputs. In this study, we propose a new 4*4 reversible logic gate, MKG. The MKG gate can be used to implement all Boolean functions. It also can be used to design efficient adders. One of the prominent functionalities of the MKG gate is that it can work singly as a reversible full adder unit, which is a versatile and widely used element in digital design. Thus, the proposed reversible full adder contains only one gate. It is shown that the proposed reversible full adder is better and optimized in terms of number of reversible gates, number of garbage outputs and number of constant inputs with compared to the existing counterparts.