How long have musical instruments been in existence?

This depends on what is defined as a musical instrument. In very ancient civilizations humans likely used non-durable materials to create rhythm or music. These likely included animal skins, wood and other materials that long ago degraded with no remaining physical record. If one defines the first musical instrument as a device specifically made for the purpose of creating a musical melody, it is likely the simple flute. But there is debate about when the first flute was made, ranging from 40,000 to 60,000 years ago.