The aim of this study was to examine the relationship between mood, alertness and calmness and particular musical elements; tempo and key signature. A sample of 44 participants was used and each participant was presented a song to listen to. A measure of mood was also noted before and after the song was presented and the MDMQ (Multi-Dimensional Mood State Questionnaire) was used to obtain measures of mood, alertness and calmness after the song. Song familiarity, preference in genre and levels of musical/classical training were also taken into account. Results found there was an increase in mood when presented with a song in a minor key and a fast tempo and also that there was a gender difference in mood change from before and after the song was presented. This has some implications for music psychology and musical therapy that are discussed and some limitations surrounding the sample size and methodology were also stated. Possible future directions in research were presented in order to forward the current study’s direction into improving the area of music therapy.