• Child traumas, attachment styles and social cognition were assessed in bipolar adults. • Participants were grouped: secure vs insecure (anxious, avoidant) attachment styles. • Participants with insecure attachment styles had more psychiatric hospitalizations. • Attachment anxiety was associated with childhood trauma but improved social cognition. • Social cognition in bipolar disorder is associated with the quality of early relational context. • Limitations include cross-sectional study design, use of self-report measures. Individuals with Bipolar Disorder (BD) present problems in Social Cognition (SC), a process associated with the quality of early attachment experiences. The experience of traumatic events in childhood threatens the quality of attachment. Attachment theory provides a comprehensive paradigm for understanding the role of early adversity on psychological functioning. However, early experiences have been largely neglected in BD research and clinical practice. We examined the moderating role of attachment in the relationship between childhood traumatic experiences and SC in a sample of 76 adults with BD. Early traumatic experiences were assessed using the Childhood Trauma Questionnaire (CTQ), SC was measured with the Hinting Task Test and attachment was examined using the Experience in Close Relationships questionnaire (ECR). Higher scores on attachment anxiety were positively associated with early traumatic events and better SC performance. Results suggest that attachment anxiety may be acting as an adaptive strategy in bipolar people who have suffered traumatic childhood experiences. The present study was observational and cross-sectional. Therefore, findings cannot be used to infer causality. Additionally, we assessed both attachment and trauma using self-report measures. Future studies should consider longitudinal designs with observer-rated measures such as standardized interviews. Our findings reinforce the importance of early childhood experiences in the development of SC in people with BD, challenging some traditional understandings of SC deficits as part of the genetic dimension of the disorder.