PURPOSE: Parents with metastatic cancer report unique concerns and challenges when discussing their illness with their minor children. Greater understanding of parents’ communication experiences can facilitate these discussions. This study aimed to describe the challenges, approaches, and decisions related to discussing prognosis among a sample of mothers with metastatic cancer. METHODS: We conducted a web-based cross-sectional survey assessing the psychosocial concerns of 224 women with metastatic cancer who had minor children. This analysis focused on participant responses to structured and open-ended questions addressing communication with their children. We used descriptive statistics to summarize responses to the structured questions and qualitative content analysis for responses to open-ended questions. RESULTS: Nearly 80% (n = 176) reported they had discussed their prognosis with at least one of their children; 79% identified at least one barrier to these discussions. The most common obstacles were participants’ uncertainty about their illness trajectory (43%) and emotional distress associated with these conversations (41%). Qualitative analyses revealed three principles that guided mothers’ communication decisions: commitment to honesty and protection; child developmental readiness; and beliefs about the right time. Approaches to discussing prognosis included total honesty, using the language of chronic illness, gradual disclosure, waiting for questions, and emphasizing hope, love, and reassurance. CONCLUSION: This study provides further evidence of the complexity and challenges of parental communication with their children about metastatic cancer. There is a need for both clinicians and researchers to identify, test, and implement evidence-based strategies to assist ill parents with their communication concerns.