In this work, we make a comparison between the course of Modern Physics (taught on the Physics Teacher Preparation and Bachelor of Physics Programs) and the Quantum Mechanics' course taught only on the Bachelor of Physics Program. The comparison between the contents taught on the Modern Physics course and the contents taught on the Quantum Mechanics' course, was based on the most used books in the teaching of both disciplines in Brazil. We also discuss the importance of the Modern Physics course to future physics teachers. in Physics.