Background. Pharmacoepidemiological studies play a key role in optimizing pharmacotherapy for various diseases. In particular, significant progress in the treatment of rheumatoid arthritis (RA) and psoriatic arthritis (PsA) necessitates a detailed analysis of the consumption of disease-modifying antirheumatic drugs. The modern therapeutic concept for these conditions focuses on achieving and maintaining long-term remission, which positions methotrexate (MTX) as a first-line agent, characterized by high effectiveness, safety and advantageous pharmacoeconomic profiles.Objective: to investigate the characteristics of MTX use in real clinical practice among patients with RA and PsA during outpatient medical care.Material and methods. The study comprised two parts: a retrospective cross-sectional analysis of MTX consumption dynamics in 2018, 2020, and 2023 via ATC/DDD (Anatomical Therapeutic Chemical classification, ATC; defined daily dose, DDD) methodology, and a longitudinal non-interventional pharmacoepidemiological study conducted in 2023 using the medical information system “BARS. Healthcare”.Results. The ATC/DDD analysis demonstrated a significant increase in MTX consumption among patients with RA and PsA: from 302,428.6 to 319,114.3 DDDs per 1,000 patients per year for RA, and from 28,157.1 to 310,771.6 DDDs per 1,000 patients per year for PsA in 2018 and 2023, respectively. The most frequently prescribed dose of MT was 15 mg/week. The primary therapeutic combination for 55.8% of patients was “MT + nonsteroidal anti-inflammatory drugs”, with 32.7% of patients also receiving glucocorticoids (GCs) as part of this combination. The study identified a high frequency of prescriptions for proton pump inhibitors, GCs, and cholecalciferol, highlighting the activity of diseases under consideration, potential complications, and the necessity for the prevention of clinically significant drug interactions.Conclusions. The conducted study confirmed that MTX remains the main drug for the treatment of RA and PsA. The ATC/DDD analysis demonstrated a significant increase in MTX consumption in recent years, correlating with its therapeutic effectiveness and accessibility. The high frequency of concomitant prescriptions underscores the complexity of treating RA and PsA and the need for an interdisciplinary approach to ensure safety and efficacy of the therapy.