Antiphospholipid antibodies (aPL) constitute a major acquired risk factor for thrombosis. Clinical symptoms (thrombosis, pregnancy morbidity) together with aPL define the antiphospholipid syndrome (APS). Deep vein thrombosis (DVT) is the most common venous and stroke is the most common arterial thrombosis; fetal death, growth restriction, pre-eclampsia, and prematurity constitute the pregnancy morbidity. Livedo, heart valve disease, thrombocytopenia, hemolytic anemia, cognitive dysfunction, and nephropathy can also occur in aPL-positive patients. Otherwise healthy individuals or patients with other autoimmune disorders, e.g., lupus may develop aPL. The International Congress on aPL takes place every three years; traditionally, the congress has been a venue for scientists and clinicians from multiple disciplines to discuss recent innovative and important studies to prioritize research questions, and to set a roadmap for future research. During each congress, International Executive Committee Members propose and vote on a location, chair, and agenda for the next meeting. During the 14th Congress in Rio de Janeiro, Brazil in September 2013, Dr. Doruk Erkan, Associate Attending Rheumatologist at the Hospital for Special Surgery, New York, NY was elected to chair the next congress in Istanbul, Turkey in September 2016. Since 1984, 14 International Congresses on aPL have: described the clinical phenomena of APS; defined classification criteria and mechanisms based on antigen characteristics; described non-criteria manifestations; and explored new mechanisms, e.g., endothelial activation, trophoblast function, and microbiome. The field still lacks robust clinical trials, risk prediction, and precisely targeted therapies. Recent advances in both the basic and clinical sciences of APS permit us to address these deficits. At the time of the Congress, we will be poised to address new findings regarding mechanisms of antibody origin and effect, mechanisms of injury, develop new classification criteria for APS, and discuss APS clinical trials with new generation oral anticoagulants and immunosuppressive agents. The 15th International Congress on aPL will offer a comprehensive program including: evidence- based state-of-the art presentations from internationally recognized physicians and scientists; Task Force presentations; oral and poster submitted abstract presentations; meet the expert workshops; satellite symposiums; and patient education workshops. The format of the meeting is novel in that 20 teams chaired by the Scientific Planning Committee, prior to the meeting, will present tentative answers to general aPL/APS questions derived from evidence-based literature review and discussions. These teams will include points of view from different disciplines in each discussion to consolidate existing knowledge and guide new research. The meeting will produce a ?State-of-the-art? APS Text Book?.