Researchers have been placing an increased importance on discovering what variables contribute to better prognosis during behavioral interventions for children with autism. This article preliminarily identifies sleep problems that may exacerbate symptoms of autism; thus, possibly influencing effectiveness of daytime interventions. A data-base of parent report of sleep problems of children with autism (N=55), ranging from 5 to 12 years of age (M=8.2 years) was evaluated. Results suggested that fewer hours of sleep per night predicted overall autism scores and social skills deficits. Similarly, stereotypic behavior was predicted by fewer hours of sleep per night and screaming during the night. Increased sensitivity to environmental stimuli in the bedroom and screaming at night predicted communication problems. Finally, sensitivity to environmental stimuli in the bedroom also predicted fewer developmental sequence disturbances. The results indicate that sleep problems and the diagnostic characteristics of autism may be related. However, future research must be completed to determine the specific relationship.