Background: Individuals with certain pre-existing chronic health conditions have been identified as a high-risk group for fatalities of COVID-19. Therefore, it is likely that individuals with chronic diseases may worry during this pandemic to the detriment of their mental health. This study compares the mental health of Bangladeshi adults affected by chronic disease to a healthy, matched control group during the COVID-19 pandemic. Method: A matched case–control analysis was performed with data collected from 395 respondents with chronic diseases and 395 controls matched for age, gender and residence. Inclusion criteria for cases were respondents who self-reported having asthma, cardiovascular symptoms and/or diabetes. Respondents were recruited using an online survey, which included the DASS-21 measure to assess stress, anxiety, and depression. Chi-square tests, Fisher’s exact tests and a conditional logistic regression were performed to examine associations among variables.Results: The prevalence estimates of stress, anxiety and depression were significantly higher among cases (73.7%; 59%; 71.6%, respectively) than among controls (43.3%; 25.6%; 31.1%). Chi-square tests showed significant associations between having chronic diseases and mental health outcomes. A conditional logistic regression showed that respondents with asthma, diabetes, cardiovascular symptoms, or any combination of these diseases had higher odds of feeling stress, anxiety, and depression than healthy individuals. Conclusion: These results underscore a subpopulation vulnerable to mental health consequences during this pandemic and indicate the need for additional mental health resources to be available to those with chronic diseases.