Objective: Posttraumatic stress disorder (PTSD) and posttraumatic stress symptoms (PTSSs) are common for parents of children with life-threatening illnesses or injuries. The impact of these psychological sequelae on parents’ personal use of health services is unknown. The present study aimed to investigate whether PTSS severity prospectively predicts increased health service utilization (HSU), and to examine the relative importance of other predisposing and enabling factors in predicting HSU. Method: The sample comprised 106 parents of children with various life threatening illnesses, who completed a resource use questionnaire at 19 months following their child’s diagnosis or admission. HSU was assessed as reported general practitioner and psychologist visits. Results: Parent PTSS severity at 7 months following their child’s diagnosis or hospital admission predicted being in higher service utilization categories in the following 12 months; as PTSS score increased, the odds of being in higher categories increased. Hierarchical ordinal logistic regression procedures indicated predisposing and enabling factors failed to further explain HSU. Conclusions: These findings highlight the importance of PTSSs to HSU and are consistent with studies of samples experiencing other forms of trauma, such as war or natural disaster. Our results also suggest that an individuals’ need, in terms of the severity of their PTSSs, appears most important in predicting their health service engagement. Although this is positive, the effectiveness of this service use, in terms of cost and outcomes, remains unclear. Further, despite the levels of PTSSs observed in the present sample, a minority of individuals sought psychosocial care.