OBJECTIVE: To examine the acceptability and feasibility of coding observed verbal and nonverbal behavioral and emotional components of mother-child communication among families of children with cancer. METHODS: Mother-child dyads (N=33, children ages 5-17 years) were asked to engage in a videotaped 15-min conversation about the child’s cancer. Coding was done using the Iowa Family Interaction Rating Scale (IFIRS). RESULTS: Acceptability and feasibility of direct observation in this population were partially supported: 58% consented and 81% of those (47% of all eligible dyads) completed the task; trained raters achieved 78% agreement in ratings across codes. The construct validity of the IFIRS was demonstrated by expected associations within and between positive and negative behavioral/emotional code ratings and between mothers’ and children’s corresponding code ratings. CONCLUSIONS: Direct observation of mother-child communication about childhood cancer has the potential to be an acceptable and feasible method of assessing verbal and nonverbal behavior and emotion in this population.