Surgical site infection (SSI) is the most common complication after surgery and represents a substantial global healthcare burden. Planning on how best to reduce SSI at an international level has been hampered by a paucity of data, particularly from countries with a low or intermediate Human Development Index (HDI) . To address this knowledge deficit, the GlobalSurg Collaborative — a body representing practicing surgeons around the world — conducted a prospective cohort study of SSI after gastrointestinal surgery in 343 hospitals worldwide. SSI incidence varied by country HDI, with 23.2% of patients in low-HDI settings experiencing an SSI versus 9.4% of patients in high-HDI settings. For cases in which a microbiology culture result was available, SSIs resistant to the prophylactic antibiotic used were found in 35.9% of patients in low-HDI countries, compared with only 16.6% of patients in high-HDI countries.