Aim: We aimed to investigate the relationship of fluor-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) with clinical, laboratory pa rameters and conventional radiographs in patients with rheumatoid arthritis (RA). Patients, material, methods: 25 patients with RA diagnosis were evaluated by sociodemo, graphic, clinical [duration of disease (year), the joints in which the complaints started, most recent joint involvement]; other parameters used in RA-specific clinical assessment [Steinbocker functional staging, disease activity score 28 (DAS 28 score), health assess, ment questionnaire score (HAQ score), general RA assessment (patients' and physicians' global assessment), patients' assessments of "pain and general health condition (visual analog scale)], laboratory, radiological [conventional radiology of hand and foot joints], positron emission tomography [F-18 FDG PET visual total score and maximum standardized uptake value (SUVmax) total score] parameters. Results: No significant correlation was detected between the F-18 FDG PET total score and SUVmax total score of the patients and clinical, laboratory, and radiological parameters (p > 0.05). There was no relationship between the cut-off values determined according to the disease activity and F-18 FDG PET/SUVmax total values (p > 0.05). Conclusions: In our study, no relationship was found between disease activity demonstrated by F-18 FDG PET/CT in RA patients and clinical, laboratory, and radiological parameters. F-18 FDG PET/CT appears to be a more sensitive method in demonstrating disease activity compared to other evaluated methods.