Background: Several studies link cytokines with inflammation and its role in unstable coronary syndromes, suggesting a link between plaque inflammation & plaque rupture. IL-1β being a prototypical proinflammatory cytokine has been linked to playing a role in unstable & stable anginal syndromes, however, the exact role it plays, the relationship between circulating levels & local effects and an understanding of cause & effect, were issues remaining under research. Objectives: to estimate IL-1β level & trace its significance in unstable vs. stable angina. Methods: a number of patients with stable & unstable angina (38) together with a number of controls (15) were subjected to IL-1β serum estimation, and other relevant investigations. Results: IL-1β serum level was found to be significantly higher in both unstable & stable angina groups versus control group. It was also found to be significantly higher in the unstable group versus the stable angina group. Conclusion: our results suggest that circulating levels of the proinflammatory cytokine IL-1β play a specific role in the pathophysiology of CAD and contribute to the pathogenesis of unstable angina as they correlate with stability (or instability) of the clinical anginal syndrome.