This pilot study investigated the utility of a cognitive-behavioral model in understanding insomnia in early-stage lung cancer patients. Nineteen patients meeting criteria for insomnia and a comparison group of 13 patients not meeting these criteria completed questionnaires assessing dysfunctional sleep-related thoughts, poor sleep hygiene, lung cancer symptoms, mood, quality of life, and insomnia symptoms. Participants also completed standard sleep logs and wore an Actiwatch while sleeping each day for 7 days. Findings indicated that the insomnia group reported significantly more dysfunctional sleep-related thoughts, higher levels of pain and anxiety, and lower quality of life than those in the comparison group. Men in the insomnia group reported significantly higher levels of fatigue than men in the comparison group, whereas women demonstrated no group differences. These pilot findings support the utility of the cognitive-behavioral model in understanding insomnia in early-stage lung cancer patients and the hypothesis that insomnia is related to poor clinical status.