Obstructive sleep apnea (OSA) and insomnia are the two most common sleep disorders. The coexistence of these conditions, termed comorbid insomnia and sleep apnea (COMISA), has been increasingly recognized, with evidence suggesting a bi-directional relationship that exacerbates the severity of each disorder. This prospective recruited 170 consecutive patients with OSA, categorized into OSA alone and COMISA group. Among recruited patients, 68 (40%) were identified with COMISA. No significant differences were found in age, gender, or body mass index between COMISA and OSA alone groups. However, COMISA patients were more likely to have comorbid medical conditions, reported worse sleep quality, and exhibited higher levels of anxiety and depression. Sleep architecture and the distribution of the low arousal threshold endotype, a potential contributor to COMISA, did not significantly differ between patients with COMISA and OSA alone. Our results suggest that COMISA is prevalent among Asian patients with OSA and is associated with worse subjective sleep quality, adverse health conditions, and higher psychological distress. However, objective sleep architecture and arousal threshold endotypes do not significantly differ from OSA alone. Further research is needed to explore the pathophysiological mechanisms underlying COMISA and optimize treatment approaches.