Most art therapists decide to become registered and certified. To become an ATR (Art Therapist Registered), you must graduate from an art therapy program approved by the American Art Therapy Association. You must also accumulate 1,000 hours of direct client contact. To become an ATR – Board Certified, an advanced level of certification, you must have a master's degree and pass a national exam. This is in addition to fulfilling the requirements for the ATR.