The Swiss HIV Cohort Study (SHCS) provides a unique research platform for clinical, translational, epidemiological, social and basic research. The SHCS was established in 1988. It is an ongoing, multicentre, clinic-based, prospective, longitudinal, observational study including HIV-infected adults in Switzerland. The study design provides continuous enrolment and semi-annual study visits, where sociodemographic and clinical and laboratory information is collected. Patients are recruited by all university hospitals in Switzerland, by numerous regional hospitals and by private physicians. In the participating institutions, all HIV-infected patients are asked to participate in the SHCS. The participation is voluntary and an informed consent is needed. The SHCS has a growing biobank including over 1.7 million aliquots of plasma and peripheral blood mononuclear cells (PBMCs), which were collected over the past 32years. Today, the SHCS is a powerful tool to study different aspects of the HIV infection such as challenges of antiretroviral treatment, including drug resistance and drug-drug interactions, coinfections, comedications and comorbidities, social and gender aspects of the disease, virus-host interactions in particular determinants of the development of broadly neutralizing antibodies, viral reservoir studies, cell biological and virus and host genetic mechanisms of the disease, transmission of HIV on a population level and pregnancy outcomes. By the end of 2019, a total of 20 845 individuals were included in the SHCS, of whom 9816 patients were still under follow-up. The SHCS was approved by the local ethical committees of all participating institutions.