Chronic insomnia is a highly prevalent disorder in general and young adult populations, and contributes a significant economic burden on society. Previous studies have shown healthcare utilization (HCU) is significantly higher for people with insomnia than people without insomnia. One limitation with previous research is accurate measurement of HCU in people with insomnia is difficult due to a high co-morbidity of medical and mental health problems as well as varying operational definitions of insomnia. Assessing HCU in people with insomnia can be improved by applying research diagnostic criteria (RDC) for insomnia, using a population with low rates of co-morbid medical/mental health problems, and measuring HCU with subjective, objective, and predictive methods. The current study found young adults with chronic insomnia had greater HCU than normal sleepers, specifically on number of medications, and chronic disease score (CDS) estimates of total healthcare costs, outpatient costs, and predicted number of primary care visits. The presence of a medical and/or mental health problem acted as a moderating variable between chronic insomnia and HCU. Simple effects testing found young adults with chronic insomnia and a medical/mental health problem had the greatest HCU followed by normal sleepers with a medical/mental health problem, chronic insomnia, and normal …