Objective: Individuals with chronic diseases are at the forefront of groups that are most affected psychologically by the coronavirus disease 2019 pandemic. Psychological changes which are experienced in this process may affect the self-care management of patients with chronic diseases in the risk group. This study aimed to determine the effect of anxiety and fear experienced in individuals with chronic diseases on self-care management during the coronavirus disease 2019 pandemic. Methods: The research is a descriptive cross-sectional study that was conducted at a public hospital between between April and June 2021. Data were obtained from 150 outpatients with chronic diseases using the Patient Information Form, Self-Care Management Process in Chronic Illness Scale, Fear of Coronavirus Disease 2019 Scale, and Coronavirus Anxiety Scale. Results: A positive, weak, and moderately strong and significant correlation between the total score of the Self-Care Management Process in Chronic Illness Scale, self-protection and social protection sub-dimension scores, and Fear of Coronavirus Disease 2019 Scale (r = 0.286, P < .001; r = 0.512, P < .001; r = 0.423, P =< .001, respectively) was noted. A very weak and significant relationship was found between Coronavirus Anxiety Scale and social protection sub-dimension scores (r = 0.176, P = .031). Also, it was found the Fear of Coronavirus Disease 2019 Scale score affected the Self-Care Management Process in Chronic Illness Scale total score and sub-dimension scores. Conclusion: The findings reveal that the self-care management of patients with chronic diseases was above the moderate score, their fear levels were close to medium, and their anxiety levels were low. Moreover, a medium level of fear positively affected the self-care management of those patients.