We describe a protocol with which we achieved a 93% success rate in acquiring high quality MRI scans without the use of sedation in 2.5-4.5 year old children with autism, developmental delays, and typical development. Our main strategy was to conduct MRIs during natural nocturnal sleep in the evenings after the child's normal bedtime. Alternatively, with some older and higher functioning children, the MRI was conducted while the child was awake and watching a video. Both strategies relied heavily on the creation of a child and family friendly MRI environment and the involvement of parents as collaborators in the project. Scanning very young children with autism, typical development, and developmental delays without the use of sedation or anesthesia was possible in the majority of cases.