Studies regarding the relationship between attachment and psychopathology during adolescence have been performed separately for clinical and nonclinical adolescents and have used different assessment measures, which together might produce a methodological bias that increases the association between attachment and psychopathology. With the aim of avoiding this bias, the present study used identical measures to explore the relationship between attachment styles and internalizing or externalizing symptoms in clinical and nonclinical groups of adolescents. The sample consisted of 258 adolescents,129 clinical and 129 nonclinical, aged between 14 and 18 years. The adolescents in each group were matched for age, gender, and socioeconomic status. Attachment was assessed using the CaMir Q-sort,(Pierrehumbert et al., 1996) and psychopathological symptoms were assessed by means of the Youth Self Report (YSR). The relationships between attachment and psychopathology were similar for clinical and nonclinical adolescents. In both groups a preoccupied attachment style predicted internalizing and externalizing symptoms, somatic complaints, anxious-fearful behavior, verbal aggression, attention-seeking behavior, and thinking problems. Compared to previous studies, this research has made it possible to identify broader, stronger, and more specific associations between preoccupied attachment style and psychopathological symptoms in adolescents.