Objectives: To compare the efficacy between platelet-rich plasma (PRP) and corticosteroids (CS) in improving magnetic resonance imaging (MRI)-detected synovitis in correlation with clinical complaints among patients with lumbar facet joint (FJ) disease.Methods: This study was carried out at Eldemerdash Hospital, Cairo, Egypt between September 2019 and January 2021. A prospective, randomized, comparative, single blinded study included 30 patients with lumbar Original ArticleFJ disease, divided into 2 equal groups, received PRP and CS injections. Patients were comparatively assessed before and after the intervention according to number of tender lumbar FJs, maximum active lumbar extension range of motion, LBP visual analogue score, LBP functional disability questionnaires and MRI lumbar FJ detected synovitis and their grading.Results: Both groups showed a significant improvement in all mentioned parameters at follow-up after 3 months. However, PRP injections promoted better performance in terms of MRI synovitis grade in all lumbar FJ levels compared to CS injections. Conclusion:Both PRP and CS injections were effective in improving MRI-detected FJ synovitis while concurrently improving all examined parameters at follow-up after 3 months. However, PRP promoted better improvement in MRI-detected synovitis grade, suggesting that it may be a better treatment option for longer duration efficacy.