The present work describes Mindtrack, a Brain-Computer Musical Interface that uses real-time brainwave data to allow a user to expressively shape progressive music. In Mindtrack, the user wears an electroencephalogram (EEG) EMO-TIV Insight headset. The raw EEG data is converted into brain wave components, followed by high-level EEG characteristics (such as emotion) that are used to control the music’s tempo and key sig-nature. Other musical parameters, such as harmony, rhythm and melody are specified by the user. Tempo and key are calculated according to the emotion detected from the EEG device. In Mindtrack, the brain is the sole instrument used to translate emotions to music. Mindtrack has the potential to increase the quality of life for persons with physical impairments who still desire to express themselves musically. Furthermore, Mindtrack can be used for music therapy, recreation, and rehabilitation.