Sensitivities of three-layer and four-layer planar waveguide sensors having metamaterial as guiding layer are analyzed for p-polarization of incident light and compared with existing results. Proposed sensors show improved cover layer sensitivity for each case of the cover layer refractive index. Also, proposed sensors demonstrate improved adlayer sensitivity for different values of adlayer thickness and adlayer refractive indices. It is observed that metamaterial has increased the evanescent field due to the unconventional nature of it, by which values of cover layer sensitivity as well as adlayer sensitivity are enhanced.