Objective: Investigate the sleep hygiene and quality of emerging adults with a CMC compared to healthy peers as well as potential predictors of sleep quality. Participants: College students with and without a CMC (n = 137 per group; aged 18-23 years) at a Midwestern university. Methods: Participants reported on anxious and depressive symptoms, sleep quality, sleep hygiene, and illness uncertainty. Results: College students with a CMC reported poorer sleep quality (Adolescent Sleep Quality Scale-Revised) and hygiene (Adolescent Sleep Hygiene Scale-Revised) than the non-CMC group. The indirect effect of internalizing symptoms on sleep quality via cognitive-emotional arousal was only significant in the CMC. Illness uncertainty demonstrated a significant indirect effect on sleep quality though the consecutive influence of internalizing symptoms and cognitive-emotional arousal. Conclusions: Emerging adults with CMCs may experience poorer sleep outcomes than peers. Illness uncertainty, internalizing symptoms, and cognitive-emotional arousal appear relevant to sleep outcomes, suggesting clinical implications for these constructs.