This chapter provides an overview of working with clients who present with more complex trauma. Many of the clients that come for Eye Movement Desensitization Reprocessing (EMDR) will have a history of complex trauma or a chaotic childhood. Clients who have experienced complex trauma may lack basic life skills or have missed out on developmental stages due to a chaotic childhood, for example, parents who were absent, neglectful, or abusive. Clients may not have been taught how to regulate their emotions in early childhood. They may present with impulsive, risk-taking, or suicidal behaviors. Before carrying out the desensitization phase of EMDR, individuals need to have an adequate level of resilience and be sufficiently resourced. Clients with Dissociative Identity Disorder (DID) display at least two distinct and enduring “alters” or identity states that recurrently take control of their behavior.