In literature nothing is known about the clinical significance of Ultra High Risk (UHR) symptoms in children and adolescents with diagnosis of obsessive–compulsive disorder (OCD). In this study, we examined the prevalence of UHR symptoms and their relationship with severity of obsessive–compulsive symptomatology, global, social, and role functioning, and level of associated depressive symptoms in a clinical sample (n = 51) of children and adolescents aged between 8 and 17 years with a diagnosis of OCD. The prevalence of UHR symptoms in this sample was 43.1%. We divided the whole sample into two groups: children and adolescents with OCD and UHR symptoms (n = 22) and children and adolescents with OCD without UHR symptoms (n = 29). Our findings suggest that the group with OCD and UHR symptoms shows worse global, social, and role functioning than the group with OCD without UHR symptoms. No differences were found on the severity of obsessive–compulsive symptomatology, the number of psychiatric diagnoses associated, and the level of depressive symptoms. The presence of UHR symptoms in children and adolescents with OCD could cause significant functional impairment and should be considered in order to plan specific and targeted therapeutic interventions.