Due to unique feature of high electric field confinement in low refractive index slots, microresonators based on cavities with a slot were investigated for novel sensing and nonlinear applications. The resonance properties of such slot resonators are significantly affected by the position of the slot inside the cavity. In this work we investigate this dependence numerically. Consistent handling of discontinuous fields and efficient resolution of sub-wavelength slot pose a numerical challenge in simulation of slot microresonators. We address these difficulties by modelling the slot resonators using coupled mode theory. Using this model, effects of the slot position on the resonances of the slot microresonators are analyzed. © 2010 IEEE.