Objective: In this study, we assessed the usefulness of a previsit questionnaire for children who were referred for an initial evaluation in a mitochondrial subspecialty clinic. We explored the themes regarding parent's questions, concerns, and goals. We aimed to add to existing knowledge about the usefulness of previsit questionnaires in a pediatric specialty setting from the perspective of parents, the specialist, and the clinical coordinator. Method: We enrolled 25 patients and their parent(s) over 25 months. Questionnaires were completed by the parent(s), the clinical coordinator, and the mitochondrial specialist. Descriptive statistics and thematic analysis were used to summarize results. Results: Parental responses suggested that they are most concerned about their child's clinical problems, communication, language and developmental delays, disease progression and prognosis, understanding mitochondrial disease, quality of life, and physical challenges including muscle and energy problems. Parents felt the previsit questionnaire was very helpful for both the doctor and for themselves to be prepared for their visit. The specialist and the clinical coordinator also found it to be helpful. Parental comments suggested that they felt that writing down the story of their child's life was helpful for the provider, allowed time for reflection, and improved the appointment experience. Some felt it was a difficult or redundant activity. Conclusion: Parents were often pleased to complete the previsit questionnaire. This allowed them to highlight concerns and share information that they wanted the care team to know about their child. We revised the tool based on feedback from parents and the specialist and will continue to use it in our clinic.