Background: The antiphospholipid syndrome (APS) is an autoimmune systemic disorder that carries many mortality and morbidity. Many cytokines come up in APS; IL6 is one of this cytokines. Objective: Assessing Circulating Level of Interleukin 6 (IL 6) and its relations to thrombotic risk in patients with primary APS. Patients and Methods: This study was carried out on sixty patients suffering antiphospholipid syndrome, and thirty healthy volunteers as a control. They were selected from inpatient and outpatient clinic of Internal Medicine and Unit of Immunology Departments from Al-Azhar University Hospitals (Al-Hussein, New Damietta and Al-Azhar University Hospitals), during the period from November 2017 to December 2019. They were divided into three equal groups: Group A; suffering from primary APS, Group B; suffering from secondary APS, Group C; healthy normal volunteers as a control group. All patients and controls were subjected to complete history, clinical assessment and laboratory investigations. Serum level of interleukin-6 was assessed. Results: There was a statistical significant increase in IL6 among patients with 1ry APS as well as patients with 2ry APS. The commonest presentation among our studied patients with 1ry APS was venous thrombosis (17%) arterial thrombosis (9%) and unexplained abortion (10%). The significant signs that were detected on general examination of those patients were livedo reticularis (10%), Raynoud phenomen (15%) and purpuric eruption (13%). As regard 2ry APS, the commonest presentation among studied patients was venous thrombosis (23%) arterial thrombosis (24%) and unexplained abortion (12%). The significant signs detected on general examination of those patients were livedo reticularis (6%), Raynoud phenomen (10%), and purpuric eruption (13%). As regard the mean IL-6, there was a high significant difference between 1ry APS, 2ry APS and control groups (P<0.001). This study showed a positive correlation of IL-6 with arterial thrombosis among patients with 1ry APS. No correlation was detected between IL-6 and arterial thrombosis among patients with 2y APS. Regarding the correlation between venous thrombosis and IL-6 in patients with 1ry APS and 2ry APS, there were no statistically significant positive correlations as regard IL6. Conclusion: IL-6 was found in patients to be elevated with primary APS. Serum IL-6 was showed to be positively correlated with arterial thrombosis.