We examined the occurrence and characteristics of self-stimulatory behaviors in 10 nonhandicapped children and 5 children with developmental delays. Each child with a developmental delay was matched with two normal comparison children, one for chronological age and the other for mental age. The subjects were videotaped in four everyday settings. It was found that few differences existed between the children with developmental delays and their age-matched pairs in the percentage of time they engaged in self-stimulatory behavior, the variety of self-stimulatory behavior, how fast or slowly a behavior was preformed, or the degree of perseveration of each of the behaviors. However, the children with developmental delays and their mental age matches displayed higher levels of obvious and gross motor behavior than the chronological age matches, and the children with developmental delays were more likely to be visually oriented towards their behavior than their age-matched pairs. A measure of judged bizarreness of various self-stimulatory behaviors indicated that obvious gross motor behaviors received the highest bizarreness ratings.