Background: Insomnia is a significant public health problem that is remained under-recognized, under-diagnosed, and under-treated. Geriatric specialists hardly diagnosed and treated insomnia. Objectives: The main purpose of this research is to determine the prevalence of insomnia and its relation to some chronic diseases in the elderly population of Arar, Saudi Arabia. Methods: A cross-sectional study, including 138 elderly patients who attended five randomly selected primary healthcare centers in Arar city was performed. All the elderly who attended the centers during the study period were invited to participate in this study. Each respondent was interviewed separately, their answers were examined to collect the needed data and fill the questionnaires. Results: The prevalence of insomnia in this study was 25.4%. Only 7.2% of the respondents were current smokers and around 24% were previous smokers. Around half (45.7) of the respondents were suffering from chronic hypertensives, and 37.0% from diabetics. Considering the sociodemographic factors association with insomnia, the age group was significantly associated with insomnia (P=0.029). There was a non-significant association with gender, BMI group, or marital status. There was a significant relation between insomnia and bronchial asthma (P=0.020), while there was a non-significant relation between insomnia and smoking status, hypertension, or diabetes mellitus. Conclusion: The results showed that insomnia is a common complaint among the elderly population with a prevalence of 25.4%. There was a significant relationship between insomnia with age group and bronchial asthma. The study reveals that health assessment is necessary to screen out insomnia and prompt management should be provided to the elderly population of Arar, Saudi Arabia.