Hurler syndrome is the most severe form of mucopolysaccharidosis type I. There is a paucity of literature reporting the gross motor abilities of children with untreated Hurler syndrome. The purpose of this case series is to describe the gross motor abilities of one male and three female children (mean age 11.4mo [SD 3.1]; range 9.5–16mo) diagnosed with Hurler syndrome. The children were assessed using the Peabody Developmental Motor Scales, 2nd edition. Gross motor delays were present in all four children at the time of assessment, and were most evident in locomotor abilities for three of the children. All four children had range of motion limitations at multiple joints. This case series provides evidence for early gross motor delays in this population, as well as evidence for specific gross motor abilities of children with untreated Hurler syndrome. It is recommended that children diagnosed with Hurler syndrome be referred to physical therapy services upon diagnosis and that physical therapists be part of the interdisciplinary team involved in the care of children with Hurler syndrome.