Results were combined from representative surveys of health related quality of life (HRQoL; n=11,877; age range=16-104) with data from a randomized controlled trial of cognitive behavior therapy for chronic insomnia (n=209; age range=31-92). Secondary analyses of scores from the SF-36 measure of HRQoL were conducted in order: (a) to compare the health related quality of life profiles of adult hypnotic users with chronic insomnia with those of population norms, and (b) to assess the impact of cognitive behavior therapy (CBT) for insomnia on HRQoL outcomes over 6 months. Compared with the primary care reference values, HRQoL among the trial participants at baseline was generally poorer. The magnitude of these decrements reduced markedly with advancing age. In the evaluation of the CBT intervention, statistically significant differences in SF-36 scores in favor of the intervention were present for physical functioning, emotional role limitation, and mental health over 6 months. Overall, this study shows that the SF-36 can play an important role in describing HRQoL in this patient group, and in the evaluation of interventions within this group.