Insomnia and snoring are common sleep disorders. The aim was to investigate the association of having a combination of insomnia symptoms and snoring with comorbidity and daytime sleepiness. The study population comprised 25,901 participants (16-75 years, 54.4% women) from 4 Swedish cities, who answered a postal questionnaire that contained questions on snoring, insomnia symptoms (difficulties initiating and/or maintaining sleep and/or early morning awakening), smoking, educational level, and respiratory and nonrespiratory disorders. Snoring was reported by 4,221 (16.2%), while 9,872 (38.1%) reported ≥ 1 insomnia symptom. A total of 2,150 (8.3%) participants reported both insomnia symptoms and snoring. The association with hypertension (adjusted odds ratio [OR], 1.4; 95% confidence interval [CI], 1.2-1.6), chronic obstructive pulmonary disease (adjusted OR, 1.8; 95% CI, 1.3-2.4), asthma (adjusted OR, 1.9; 95% CI, 1.6-2.3), daytime sleepiness (adjusted OR, 7.9; 95% CI, 7.1-8.8), and the use of hypnotics (adjusted OR, 7.5; 95% CI, 6.1-9.1) was highest for the group with both insomnia symptoms and snoring. Participants with both snoring and insomnia run an increased risk of hypertension, chronic obstructive pulmonary disease, asthma, daytime sleepiness, and use of hypnotics. It is important to consider snoring in patients seeking medical assistance for insomnia and, vice versa, in patients with snoring inquiring about insomnia. Hägg SA, Ilieva E, Ljunggren M, etal. The negative health effects of having a combination of snoring and insomnia. J Clin Sleep Med. 2022;18(4):973-981.