The project goal is to develop a tool for detecting music plagiarism by comparing melodies. First, the fundamental frequencies of the melody are extracted from two sections of songs where one is suspected of being a melody plagiarism of the other. Different algorithms dealing with melody extraction from monophonic and polyphonic music were tested. The algorithm chosen is Durrieu algorithm, based on audio signal modeling and parameter estimation. After melody extraction, a comparison between the extracted fundamental frequencies of the two songs is performed. This comparison aims to determine, based on criteria of similarity between the melody sequences, whether one is a melody plagiarism of the other. The comparison process is performed using the DTW algorithm, an algorithm that measures similarities between two sequences. The developed system can identify cases of plagiarism for polyphonic music. The system yields the expected results for known plagiarism songs.