Background: Medical students, as a part of the first line of combating COVID-19, have been exposed to harm caused by mental disorders. Objectives: This study investigated how stress management training affects the mental health of medical students and interns during the COVID-19 pandemic.
 Methods: sixteen training and internship students of Birjand University of Medical Sciences from 2020-2021 were included in this intervention study. The intervention group completed the stress management training course in 6 sessions. Mental health dimensions were collected with the SCL90 questionnaire before and after intervention in both groups. SPSS 22 software and Mann-Whitney U-test, Wilcoxon, Chi-square, and Fisher’s exact test were utilized for data analysis.
 Results: The basic data showed no significant differences between groups (P > 0.05). After the intervention, the mean scores of physical complaint, obsessive-compulsive, interpersonal relations, depression, anxiety, aggression, fear, paranoid and psychotic dimensions in the intervention group significantly decreased (P < 0.05). In controls, the obsessive-compulsive, depression, anxiety, and aggression dimensions significantly decreased (P < 0.05). However, in controls, there was no significant difference in the mean score of other dimensions before and after intervention (P > 0.05). Before the intervention, the frequency distribution of various levels of sensitivity to interpersonal relationships in the two studied groups was the same (P > 0.05); after the intervention, these levels were significantly different between groups (P < 0.05). After intervention, the control group had a higher frequency distribution of individuals with degrees of depression (P < 0.05).
 Conclusions: The mental health of medical internship students during a crisis can be improved by stress management training, which reduces anxiety and depression. Therefore, stress management courses are recommended in stressful situations.