Separation Anxiety Disorder (SAD) is currently the most prevalent, yet most under-researched anxiety disorder in childhood. To date, there have been few studies investigating the efficacy of interventions for young children with SAD. The primary purpose of this paper is to describe the process of tailoring Parent Child Interaction Therapy (PCIT) for young children aged 4-8 with SAD. The paper provides a theoretical rationale for using PCIT to treat young children with SAD. The first randomized clinical trial for young children with SAD is then described. The paper focuses on the process of adapting PCIT to make it most relevant for children with SAD. The specific challenges and rewards of conducting PCIT with anxious children and their parents are presented.