Nerve growth Factor (NGF) is a neurotrophic factor which has animportant role in the development and functions of the central and theperipheral nervous systems, Moreover , NGF influences the development ,differentiation, chemotaxis and the release of the inflammatory cells aswell as fibroblasts activation through a complex network influenced byother proi nfl animator), cytokines.The aim of our study is to detect the levels of NGF in the serum andthe synovial fluids of patients with Rheumatoid arthritis, Juvenilerheumatoid arthritis and osteoarthritis and to detect its correlation with theactivity of the diseases.This study was carried out on one hundred subjects attending theRheumatology and Rehabilitation Department. Zagazig universityhospitals.The subjects were classified into 4 groups:Group I: Included 30 patients with RA..Group II: Included 30 patients with JRA..Group III: Included 30 patients with OA..Group IV: Included 10 apparently healthy subjects as contnol.All The subjects were subjected to the following:A — Full history taking.B—Complete clinical examination.C—Assessment of disease activity.D— Investigations :(I) laboratory:1-Complete blood Picture.2-ESR.3-CRP.4-Liver function tests.5-Rheumatoid factor titre.6-Level of Nerve growth factor (NGF) in the serum andthe synovial fluid by ELISA.(II) Radiology :Plain x ray A/P view for both hands and both knees.