This study is to investigate if intranasal oxytocin will improve hyperphagia, social skills, and behaviors in subjects with Prader-Willi syndrome. This will be a randomized placebo controlled pilot study. The primary outcome measure is to determine if intranasal administration of oxytocin will cause any adverse events in subjects with Prader-Willi syndrome. Secondarily, the investigators will also perform evaluations to determine if intranasal oxytocin has any effect on social skills, behaviors, or appetite in children with Prader-Willi syndrome.