Background/aim: The COVID-19 outbreak is known to increase stress levels of most patients with chronic diseases. Patients with Ankylosing Spondylitis (AS) and Rheumatoid Arthritis (RA) are highly susceptible to environmental stress. In the current study, we aimed to determine how the COVID-19 pandemic psychologically affected patients with chronic progressive diseases such as AS and RA and the effects of these psychological factors on disease activity.Materials and methods: Age and gender-matched patients with AS (n=80), RA (n=80), and healthy controls (n=80) were included in the study. All participants were evaluated with the "Perceived COVID-19 Threat Form (PCTF)", "Suicide-Ideation Scale (SIS)", "Hospital Anxiety and Depression Scale (HADS)", "The Ability to Cope with Trauma (PACT)" and "Psychological General Well-Being Index (PGWB)" scales. BASDAI was used in patients with AS and DAS28 was used in patients with RA to assess disease severity.Results: Compared to healthy individuals, patients with RA and AS had lower PGWB scores and higher HADS depression and anxiety subscale scores. Almost all psychometric assessment test scores were worse in AS patients with high-disease activity compared to those in low-disease activity. PACT scores were higher in patients with moderate RA compared to patients with mild RA (p=0.006). While a positive correlation was identified between BASDAI and most of the psychometric assessment test scores (r=0 .36 for PCTF, r= 0.53 for depressive scores, r= 0.54 for anxiety scores, r= 0.57 for suicidal 2 ideation), DAS28 scores were found to be associated only with PACT total and PACT perceived forward-focused subscale scores (r= -.26 and r= .33, respectively). Conclusion:Psychologically, AS and RA patients were found to be worse off compared to healthy controls. The perceived COVID threat and psychological status were associated with disease activity in AS, but not RA patients. Patients with chronic illnesses may be more vulnerable to the psychological effects of the pandemic, which can worsen disease activity.