PURPOSE: Cardiovascular complications associated with anorexia nervosa (AN) are well recognized. Whether a wide array of studies has investigated autonomic nervous system (ANS) functioning at rest in people with AN, few is yet known on their reactivity ability during stress conditions. The aim of the current study is testing ANS reactivity to a stressful task activating attachment system among adolescents with AN. METHODS: Heart rate (HR) and its variability, as derived by high-frequency-heart rate variability (HF-HRV), were continuously assessed while 13 AN patients and 12 healthy controls (HCs) responded to a set of attachment-related drawings (Adult Attachment Projective, AAP). RESULTS: Findings showed that patients with AN displayed a stronger parasympathetic activity, as indicated by generally a lower heart rate (HR) during the entire task and a higher HF-HRV for drawings eliciting dyadic interactions compared to HCs. CONCLUSION: The study findings suggest a novel understanding of cardiovascular functioning in AN. LEVEL OF EVIDENCE: Level V, descriptive study.