We conducted a survey of physician opinions in relation to enzyme replacement therapy (ERT) and extended newborn screening (ENBS) for mucopolysaccharidoses (MPS). A questionnaire consisting of hypothetical clinical scenarios about ERT and ENBS for MPS was posted on metab-L, a list server for the metabolic community. The questionnaire included similar questions to those used in previous studies that sought the views of individuals and families affected by MPS. Our aim was to compare medical professionals' opinions with that of the individuals and families affected by MPS that they serve. The questionnaire was completed by 35 physicians, most of whom were metabolic physicians. Responses differed significantly between the physician and parent groups when the clinical scenario involved intellectual impairment. In this setting, physicians were significantly less inclined to advocate the use of ERT. Comparison of the responses to the ENBS scenarios revealed that compared to physicians, family of individuals with MPS were more inclined to desire diagnosis at birth, even if no treatment could alter the outcome of the condition. Compared to the family of individuals with MPS, physicians are more likely to advocate the use of ERT and ENBS where there is proven medical benefit to the affected individual.