We have discovered some key differences between people\'s knowledge and levels among music therapists in Korea during its 10 year music therapy history. A reason for this could be the diverse populations and methodologies that our professions have had to deal with. Similarly, complex theoretical bases comes from outside of our own therapy field to induce this idea. The early development of music therapy in the US was predominantly linking theories involving behaviorism or behavioral therapy. Psychoanalytic approaches became more dominant in Europe and have become common in the East Coast during the 1970s. Existential/humanistic approaches were able to contribute to building some theoretical grounds for some of music therapy models. Other theories based on scientific research developed mostly in the area of music and medicine. Many models of music therapy were formed with a variety of approaches coming from well known theoretical orientation. According to this writer\'s recent investigation, many music therapists base their current practice on their previous schooling and practicing area, along with their age groups and academic degrees. It also affirmed that the therapists\' areas of practice significantly influenced their primary approaches. Most of all, music therapists having various theoretical orientations showed no significant difference in perceived image of their value, importance, amount use of music, satisfaction from work, previous education, and desire to expand theoretical approaches.