Objective: Anxiety, stress and burnout are observed in healthcare workers during the Covid-19 pandemic. This study aimed to determine the levels of anxiety and burnout and related risk factors in the healthcare workers and assistant personnel at a tertiary referral university hospital. Method: Hospital Anxiety Depression Scale (HADS), Maslach Burnout Inventory (MBI) and a sociodemographic questionnaire were delivered on-line to all employees of our hospital. 683 individuals were to the study who completed and returned the forms between April 15-30, 2020. Results: Stress, depression and anxiety levels were significantly higher in nurses. Emotional burnout and depersonalization symptoms were higher and personal accomplishment scores were lower in resident physicians and nurses in comparison to the other groups. Being single, having a child and living away from home were factors underlying the burnout severity. Frontline work in the Covid-19 clinics did not affect the levels of anxiety, stress and depression. On the basis of the cut off points of the HADS scores; anxiety disorder (OR: 7.19) and depression (OR 3.43) were the most relevant risk factors for emotional exhaustion. Anxiety disorder was also the main risk factor for depersonalization. Depersonalization was 2.7-fold more among the nurses complaining of being overworked. Social support from the work environment and the family was protective against depersonalization. Conclusion: Covid-19 pandemic has adversely affected the wellbeing of healthcare workers. The presence of depression and anxiety increased the risk of burnout. Social support can be expected to protect against burnout. It is, therefore, of great importance to implement urgently effective psychosocial and organizational interventions in order to protect the mental health of healthcare workers and to prevent burnout.