Mental illness is common in solid organ transplant (SOT) recipients, both in the pre- and post-transplant periods. Because mental illness often has a chronic, relapsing and remitting course, diagnosis and treatment often happen in the post-transplant setting, sometimes many years after transplant. As such, understanding the impact of solid organ transplantation on mental health and developing an approach to treating common mental health conditions in transplant recipients is critical for primary care providers. In this chapter, we will review how patients’ mental health is assessed in the pre-transplant setting, the prevalence and screening of mental health disorders post-transplant, a management approach to treating mental illness in transplant recipients, and a framework for when to refer patients for formal psychiatric care.