Background: Families of children living with a rare disease report significant health and social burden, however, few studies have systematically examined family needs by using validated tools to assess the scope and extent of this burden. Our aim was to develop a comprehensive survey to assess health, psychosocial and financial impacts on Australian families caring for a child with a rare disease. Methods: We developed a self-administered survey for parents/carers incorporating pre-validated tools. The survey included questions about experiences of diagnosis, health services use and needs, needs for peer and financial supports. Forty-seven families attending the state-wide Genetic Metabolic Disorders Service at the Children’s Hospital at Westmead, Sydney were invited to participate. Results: Of 46 families who received the survey, 30 (65%) completed it. Most (93%) found the survey acceptable and relevant (91%). Patients were 1–17 years old, 14 (47%) male, and 12 (40%) non-Caucasian. Eighteen (60%) had a lysosomal storage disease and 12(40%) had a mitochondrial disorder. Eleven (38%) saw 3–5 doctors and four (14%) saw 6–10 doctors before receiving the correct diagnosis; 43% felt diagnosis was delayed. Four (13%) were dissatisfied with the way diagnosis was given, due to insensitive style of communication, inadequate information and psychological support. Psychosocial impact was moderate to high for 90% of families and the level of impact was not dependent on the level of health functioning of the child. Twenty-six (87%) wanted, but only 13(43%) received, information about peer-support groups. The 30 children accounted for 168 visits to general practitioners and 260 visits to specialist doctors; 21 (70%) children had at least one admission to hospital, including one who had 16 admissions in the previous 12 months. Most families (77%) received financial assistance but 52% believed this was insufficient. Families benefited from a specialised multi-disciplinary clinic but called for patient-held electronic medical records. Conclusions: Australian families caring for children with genetic metabolic disorders are adversely impacted by delays in diagnosis, lack of easy access to peer support groups and lack of psychological support. Further research is needed to estimate economic impact and to analyse health service delivery models for children with rare diseases in Australia.