Tehran University of Medical Sciences Journal of Sleep Sciences 2476-2938 5 3 2021 07 10 111 116 Hossein Farrokhi School of Education Sciences and Psychology, Ferdowsi University of Mashhad, Mashhad, Iran Behnaz shid Anbarani School of Education Sciences and Psychology, Ferdowsi University of Mashhad, Mashhad, Iran Seyyed Iman Seyyedzadeh School of Education Sciences and Psychology, Ferdowsi University of Mashhad, Mashhad, Iran Atiyeh Taghavi Bojnordi School of Education Sciences and Psychology, Ferdowsi University of Mashhad, Mashhad, Iran Mahnaz Amini Division of Sleep Medicine, Psychiatry and Behavioral Sciences Research Center, Lung Diseases Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran 2020 09 01 2021 07 10 Background and Objective: In the late 2019, an acute respiratory syndrome [severe acute respiratory syndrome coro-navirus 2 (SARS-CoV-2)] resulted in a pandemic coronavirus disease (COVID-19). This study was designed to com-pare the efficacy of internet-based cognitive behavioral therapy for insomnia (ICBT-I) with online relaxation training for management of insomnia during SARS-CoV-2 pandemic. Materials and Methods: This controlled trial was conducted on adults (18-65 years) with the complaint of insomnia who called psychology call centers in Mashhad, Iran, from March to June 2020. Participants with insomnia symptoms starting after SARS-CoV-2 pandemic who had Insomnia Severity Index (ISI) scores of ≥ 15 were included in the study. Five weekly sessions of ICBT-I as the intervention were compared with 5 weekly online relaxation training sessions in the control group. ISI before and after 5 weeks of follow-up was compared in both groups. Results: From a total cohort of 144 subjects included in the study, 98 were excluded and the remainder were allocated to 23 cases and 23 control subjects. During follow-up period, 5 individuals (21.7%) dropped out in each group. The mean ISI scores improved after therapy (20.6 to 8.5 and 21.8 to 13.0 for intervention and control groups, respectively). Conclusion: ICBT-I significantly improved insomnia severity during home quarantine of SARS-CoV-2 pandemic. We suggest that ICBT-I could be an effective and feasible alternative in pandemic of an infectious disease. Clients accepted ICBT-I with a minor drop-out in our study. https://jss.tums.ac.ir/index.php/jss/article/view/173