Atopic diseases, such as asthma and allergic rhinitis, are common conditions that can influence sleep and subsequent daytime functioning. Children and patients with allergic conditions from ethnic minority groups might be particularly vulnerable to poor sleep and compromised daytime functioning because of the prevalence of these illnesses in these groups and the high level of morbidity. Research over the past 10 years has shed light on the pathophysiologic mechanisms (eg, inflammatory mediators) involved in many atopic diseases that can underlie sleep disruptions as a consequence of the presence of nocturnal symptoms. Associations between nocturnal symptoms and sleep and poorer quality of life as a result of missed sleep have been demonstrated across studies. Patients with severe illness and poor control appear to bear the most burden in terms of sleep impairment. Sleep-disordered breathing is also more common in patients with allergic diseases. Upper and lower airway resistance can increase the risk for sleep-disordered breathing events. In patients with allergic rhinitis, nasal congestion is a risk factor for apnea and snoring. Finally, consistent and appropriate use of medications can minimize nocturnal asthma or allergic symptoms that might disrupt sleep. Despite these advances, there is much room for improvement in this area. A summary of the sleep and allergic disease literature is reviewed, with methodological, conceptual, and clinical suggestions presented for future research.