In order to ensure the stable and reliable operation of the squirrel cage induction motors (SCIMs), it is very important to know their rotor temperature. The rotor overheating causes serious damages on rotor bars and end rings. The direct measurement of the rotor temperature by means of thermal sensors is expensive and the installation and utilization process of their corresponding data acquisition devices is difficult. Therefore, the estimation methods of the SCIM's rotor temperature are proposed which are classified into three main methods: parameter estimation methods, thermal model-based estimation methods, and hybrid methods. The present paper describes and analyses and compares the assumptions, requirements, advantages, and drawbacks of these methods comprehensively. This review could be useful to advance the path of the previous researches in the field of the SCIM's rotor temperature estimation and could be effective to find the novel methods with more advantages and less drawbacks in the future. (C) 2019 Published by Elsevier Ltd.