BACKGROUND: The use of smartphones is increasing in the coronavirus disease (COVID-19) pandemic for various purposes, this encourages smartphone addiction. In addition, the incidence of insomnia has also increased in the pandemic era. AIM: This study was conducted to find an association between smartphone addiction and the incidence of insomnia, especially among students of the Faculty of Medicine, Udayana University. METHOD: This research is a descriptive-analytic study with the cross-sectional method, using two main questionnaires, Smartphone Addiction Scale-Short Version, and Insomnia Severity Index. Questionnaires were distributed using Google forms and then collected and analyzed using software SPSS version 25. RESULT: Overall the total research respondents with the inclusion criteria in this study amounted to 364 people. The results showed that 212 respondents (58.24%) had a high level of smartphone addiction and 152 respondents (41.76%) had a low level of smartphone addiction. In addition, 187 respondents (51.37%) experienced mild insomnia, 87 respondents (23.9%) experienced moderate insomnia, 13 respondents (3.57%) experienced severe insomnia, and 77 respondents (21.15%) did not experience insomnia. Based on the results of data analysis, it was found that smartphone addiction had a significant relationship (p = 0.002) with weak and positive correlation (r = 0.162) to the incidence of insomnia. CONCLUSION: It was found that the majority of respondents experienced high levels of smartphone addiction and mild insomnia. Another finding suggests the higher addiction to the smartphones, the more severe insomnia suffered.