This paper addresses the application of omega media in the design of variable directional couplers. Like magnetically biased ferrites, an omega medium can also produce a field displacement effect. However, in this case, this effect is reciprocal, which suggests its application in the design of reciprocal devices. The field displacement effect can influence the coupling coefficient between two parallel coupled waveguides. In fact, instead of changing the coupling coefficient by changing the separation between the waveguides, the value of constitutive omega parameter can be used to control the mutual coupling. As an example of application, we consider the case of an omega non-radiative dielectric (NRD) directional coupler. To reach to a waveguiding structure with a closed analytical solution, we assume that both slabs are made of uniaxial omega medium.