OBJECTIVE:Explore the mental health trajectories of parents following their child's life-threatening illness/injury. METHODS:Participants were 217 parents (mean age: 34.9-40.0; 66 fathers) of 165 children who presented to a tertiary hospital with a life-threatening illness/injury. Parents completed questionnaires about their mental health and psychosocial stressors within 4 weeks of the child's illness/injury (T1), and 4 months (T2), 7 months (T3), and 19 months (T4) postdiagnosis. RESULTS:For both mothers and fathers, mental health symptoms were elevated at diagnosis declining to normal levels by T3, with a pattern of increase at T4. Fathers demonstrated a faster decline in symptoms between T1 and T2, and fathers, but not mothers, experienced a relapse in depressive symptoms at T4. Fathers reported higher rates of work changes. CONCLUSIONS:These findings have important implications for the design and timing of parental interventions to support families of children with life-threatening disease/injury.