Introduction. Psoriatic arthritis, as well as rheumatoid arthritis are presented by a heterogeneity of clinical manifestations in the early stages. Objective. Improvement of early diagnosis of psoriatic arthritis based on clinical data, laboratory and instrumental research methods. Material and methods. The study was carried out between 2019 and 2022 at the Rheumatology and Nephrology Discipline, in the arthology and rheumatology departments of the “Timofei Moşneaga” Clinical Republican Hospital. To accomplish the tasks set out in the study, 110 patients were examined, including 55 patients with psoriatic arthritis and 55 patients with rheumatoid arthritis. Results. The onset of rheumatoid arthritis had a classic variant, of polyarthritis type – 76.4%, the onset being through – radiocarpal joints (41.8%), proximal interphalangeal (47.3%) and metacarpophalangeal (58.2%) joints, the lesion was symmetrical. In those with psoriatic arthritis, the monooligoarthritic version of the onset prevailed – 63,6%, mainly the joints of the lower extremities, mainly with asymmetrical character. Conclusions. Sensitivity study of the diagnostic criteria of rheumatoid arthritis and psoriatic arthritis showed insufficient reliability for earlystage detection. Arthralgias were the most common early symptoms of rheumatoid arthritis and psoriatic arthritis, which occurred even in the prenosological period of disease. The number of swollen joints in early rheumatoid arthritis were higher (p<0.05) than in the group of patients with psoriatic arthritis. Signs of osteopenia were detected similarly in early rheumatoid arthritis and psoriatic arthritis.