Perfectionism has been identified as a vulnerability factor in the onset and maintenance of several psychological disorders and is particularly prominent in obsessive-compulsive disorder (OCD). Evidence indicates that there is a subgroup of OCD associated with high perfectionism that is characterized by greater frequency of obsessions and compulsions related to symmetry, ordering, repeating, cleaning, and hoarding. Although perfectionism-related OCD can be particularly resistant to treatment, exposure and response prevention (ERP) has been shown to be an efficacious psychological intervention. The case vignette described in this chapter illustrates the implementation of a comprehensive cognitive behavioral assessment, case formulation, and treatment plan for OCD characterized by perfectionism-driven symmetry, ordering, checking, and reassurance seeking. A detailed account of ERP is described, including constructing a multi-themed exposure hierarchy, in-session exposure practices, and expansion of between-session exposure practices to a lifestyle-management approach to challenge his obsessive thoughts across a range of situations and triggers throughout the day. Complicating factors associated with the enduring, pervasive, ego-syntonic nature of these difficulties are presented, along with strategies for building motivation, assessing therapy-interfering behaviors, and challenging obstacles in treatment.