371 Background: Identity development is the process that informs how an individual views oneself and develops a sense of self. A cancer diagnosis during adolescence and young adulthood (AYA; ages 15-39) disrupts AYAs’ identity development and creates identity distress. Identity development is a key developmental task during AYA. It is a recognized psychosocial concern and need for diagnosed AYAs but remains an understudied psychosocial need in AYA oncology care. Identity development can be promoted (or inhibited) in AYAs’ social interactions. AYAs’ communication with parents (often their primary source of support) may function adaptively or maladaptively for AYAs’ identity development. A communication skills intervention for diagnosed AYAs and parents could address communication strategies that promote AYAs’ healthy identity development while buffering identity distress. To capture knowledge that will contribute to a communication skill intervention, this study aimed to identify parent – AYA communication that promotes or inhibits identity formation. Methods: We recruited 14 AYAs to participate in audio-recorded, semi-structured, in-depth interviews. Eligibility criteria for AYAs included: 1) must be diagnosed with any type of cancer during adolescence (aged 15-18) or emerging adulthood (aged 19-29) and 2) be in active treatment or up to 32 months since the end of treatment. Interviews were thematically analyzed using constant comparative method. Results: AYAs’ age ranged from 19-29 ( M =24 years old), and their age of diagnosis ranged from 15-27 years ( M =21 years old). Diagnosed AYAs shared four types of identity disruptions that involved communication with their parents: independence, friendships, sexual orientation/behavior, and long-term goals. They also shared how parents’ communication either promoted identity development or contributed to identity distress. Results indicated that parents’ using parental psychological control in communication contributed to AYAs’ identity distress. AYAs shared parents prioritizing the AYA’s voice and engaging in emotionally supportive communication fostered their identity development. Conclusions: This study captures specific communication approaches and behaviors in parent-AYA communication and its promotion of AYAs’ identity development or contribution to identity distress. Findings demonstrate the importance of developing communication skills training and conversation tools to helps both AYAs and parents learn how to communicate to promote AYAs’ identity development and better overall psychological well-being.