Little is known about the psychosocial profiles of parents who have a child with an undiagnosed chronic illness. The National Institutes of Health Undiagnosed Diseases Network (UDN) evaluates individuals with intractable medical findings, with the objective of discovering the underlying diagnosis. We report on the psychosocial profiles of 50 parents whose children were accepted to one of the network's clinical sites. Parents completed questionnaires assessing anxiety, depression, coping self-efficacy, and health care empowerment at the beginning of their child's UDN clinical evaluation. Parents of undiagnosed children had high rates of anxiety and depression (~ 40%), which were significantly inversely correlated with coping self-efficacy, but not with health care empowerment. Coping self-efficacy, depressive, and anxiety symptoms were better in parents with older children and with longer duration of illness. Gender differences were identified, with mothers reporting greater health care engagement than fathers. Overall, our findings suggest that parents of children with undiagnosed diseases maintain positive coping self-efficacy and remain actively engaged in health care and to a lesser degree tolerance for uncertainty, but these come with a high emotional cost to the parents. As the parents' psychological needs may not be obvious, these should be ascertained and the requisite support provided.