The rotors can be balanced using two different methods: a modal method and an influence coefficient method. Until recently, it was generally viewed that the former method can be used for balancing rigid rotors, whereas the latter method for balancing flexible rotors. Nowadays, the difference in classification of rotors and the approach to balancing have changed. The study presents general differences between the two balancing methods and compares the efficiency of balancing the flexible rotor using the modal method and the influence coefficient method.