Although several studies have explored the geoepidemiology of autoimmune rheumatic diseases (ARD), trends of their frequency overtime are under-investigated. Herein, in a nation-wide study, we examine trends in the prevalence of various ARD over-time, taking also into account the Covid-19 pandemic. In this retrospective study in the entire Greek adult population (approximately 10.000.000 people), we searched the electronic prescription database of the e-Government Centre for Social Security Services using prespecified ICD-10 codes to capture all adult patients with Psoriatic Arthritis (PsA), Rheumatoid Arthritis (RA), Ankylosing Spondylitis (AS), Systemic Lupus Erythematosus (SLE), Systemic Sclerosis (SSc) and Polymyalgia Rheumatica or Giant Cell Arteritis (PMR/GCA). Two sequential 4-year periods, namely 2016–2019 and 2020–2023 were compared. Prevalence of RA, PsA, AxSpA, SLE and SSc increased significantly during 2020–2023 compared to 2016–2019. This applies to both genders and to all age groups for RA, PsA and AxSpA, to female patients in SLE and SSc and to patients 18–39 years in SLE and ≥ 60 years in SSc. Overall, there was 47% increase in prevalence for AxSpA (0.100% in 2016–19 vs 0.147% in 2020–23), 36.5% for PsA (0.148% vs 0.202%), 20.6% for RA (0.467% vs 0.563%), 19% for SLE (0.137% vs 0.163%) and 13% for SSc (0.023% vs 0.026%). A 16.3% decrease was evident in GCA/PMR, limited to those ≥ 40 years old. In a nation-wide study we confirm that ARD prevalence increases over-time, whereas a contribution of Covid-19 pandemic to our results during 2020–2023, cannot be excluded. Additional human, medical and financial resources will be needed to cover the increased needs of ARD patients.