Abstract Background Insomnia is a common complaint among individuals with migraine. The close association between insomnia and migraine has been reported in clinic-based and population-based studies. Probable migraine (PM) is a migrainous headache which fulfills all but one criterion in the migraine diagnostic criteria. However, an association between insomnia and PM has rarely been reported. This study is to investigate the association between insomnia and PM in comparison with migraine using data from the Korean Headache-Sleep Study. Methods The Korean Headache-Sleep Study is a nation-wide cross-sectional survey for all Korean adults aged 19–69 years. The survey was performed via face-to-face interview using a questionnaire on sleep and headache. If an individual’s Insomnia Severity Index score was ≥15.5, she/he was diagnosed as having insomnia. Results Of 2695 participants, the prevalence of migraine, PM and insomnia was 5.3, 14.1 and 3.6 %, respectively. The prevalence of insomnia among subjects with PM was not significantly different compared to those with migraine (8.2 % vs. 9.1 %, p = 0.860 ). However, insomnia prevalence in subjects with PM was significantly higher than in non-headache controls (8.2 % vs. 1.8 %, p