Unstable angina is one presentation of coronary heart disease and most commonly caused by a clot superimposed on a fixed coronary obstruction. Multiple studies support a role for inflammation in the pathogenesis of coronary atherosclerosis and unstable angina. There is widespread activating of neutrophiles across the coronary vascular bed in patients with unstable angina regardless of the location of the culprite lesion. This study is carried out in Al-Hawamdia general hospital, it aimed to assess serum interleukin-1 beta (IL-1β) concentrations in patients with stable and unstable angina and whether these concentrations correlate with instability or not. This study included 60 patients (30 patients with stable angina; group I and 30 patients with unstable angina ; group II) and 20 controls (group III) . This study revealed that serum levels of IL-1β were significantly higher in group I and group II than group III and also were significantly higher in group II than group I.