Parents play a prominent role in the early management of phenylketonuria (PKU). This study examines parent trauma reactions to PKU, the nature of parent concerns out PKU, and social relationship variables predicting parent trauma reactions. Questionnaires were completed by 65 mothers and 61 fathers of children aged 3 months to 12 years. Most parents reported mild levels of trauma. Intrusive reactions were more common than avoidant reactions. More mothers than fathers reported clinical levels of trauma (12% vs. 5%). Trauma scores were moderately correlated with PKU concerns. For mothers, higher levels of trauma reactions were associated with younger age of the child, perception of their partner as less caring, and smaller support networks. For fathers, higher trauma reactions were associated with younger age of self and non-English-speaking background. Results indicate the relevance of a trauma model to understanding the experience of parents caring for a child with PKU.