Background: A multi-system vasculitis illness called Bechet's disease (BD) is characterized by recurring mouth ulcers, genital ulcers, and eye problems. Objectives: to determine the sensitivity and specificity of self-saliva skin prick test versus conventional pathergy skin test with severity and activity of Bechet’s disease. Patients & methods: This case controls research was performed on 90 cases divided into: 30 Behçet’s caseshave confirmed diagnosis concerning ICBD for BD criteria updated in 2013, 30 recurrent aphthous stomatitis (RAS) cases & thirty matched healthy controls. patients were selected from the clinics of internal medicine department, especially rheumatology and immunology clinic, Beni-Suef university hospital. Results: Skin prick test with saliva revealed significantly higher sensitivity (96.7) and specificity (93.3) in diagnosis of Behçet’s disease compared to normal healthy control. Skin prick test with filtered saliva showed significantly greater sensitivity (83.3) more than skin prick test with saliva & pathergy skin test in detecting RAS patients. While Skin prick test with saliva revealed significantly greater specificity (93.3) more than pathergy skin test & filtered saliva in excluding RAS disease. Conclusion: skin prick test with neat self-saliva is reliable and cost-effective tool for diagnosing of BD, as it is accurate and inexpensive. However, it doesn't correlate with uveitis activity, so it's not recommended to use SPT NSS to predict BD uveitis.